There seems to be a pattern with combat feats that give you a use for your bonus action dealing more damage than a straightforward ability score increase. It is true for Crossbow Expert, it is almost always true for Polearm Master. Charger also gives you a use for your bonus action, so will it also lead to higher expected damage than an ability score increase? Under what circumstances?
Not meaningfully in a vacuum.
If you don't have Extra Attack, are in a situation where you can trigger charger, and don't have any good use for your bonus action, charger is nice. This is only really relevant for about 1 level, for most martial classes, where they would choose between ASI or Charger. Variant human/custom lineage is different, as they can have Charger from level 1.
The situation is important. If you are already in melee range of an enemy, leaving their reach to do a little loop and trigger charger means you eat 1 or more opportunity attacks (you must use your action to dash, not to disengage), unless you have some means to avoid opportunity attacks through racial or other ability. Which is rare at level 4. This means charger won't trigger every turn without taking an attack for the privilege, which will likely damage the charger, offsetting the value gained by the feat.
Many online guides to classes try to find some way to weaponize the bonus action, it's often assumed in optimization that this will be the case. Certain martial classes and subclasses automatically gain a use for the bonus action that is commensurate to or greater than the features charger offers.
And once Extra Attack is in play, assuming even a 16 in str/dex and a d8 weapon, charger does not keep up damagewise with 2 attacks. Most serious melee attackers will do more damage than 1d8+3 per attack, but that's already enough to outweight charger's +5, and that's if charger did that every round, which it doesn't without opportunity attacks.
A comparison of +1 attack vs +4 damage against the MM's listed AC values per CR in a big chart or whatever isn't going to change this situation (even if that was an accurate listing of AC values over monsters, which it isn't etc). The logistics of getting charger to actually deliver that damage in the first place simply aren't there outside some very niche situations (like a Wildfire Spirit consistently moving the charger away so they can re-charge) and even if it is there it stops being useful nearly ever 1 level later.
Ergo an ASI spent getting +1 to hit and damage (and whatever ability checks get used for that stat as well) will be superior at all levels other than level 4, and even at level 4 it will very likely be more useful than charger in the vast majority of circumstances.
On Rogues & Haste: A melee attacker with extra attack, the mobile feat, the charger feat, and who is under the effect of the Haste spell, could do the following; Attack normally (twice or more) with their action, spend their Haste action to dash, move away without triggering opportunity attack (thanks to mobile feat), and then move back to the original target (or another target) in a 10' straight line, attack as a bonus action with +5 damage (and then keep moving somewhere if they wanted to with the rest of their immense movement (30 + 10 (Mobile) x 2 = 80', -20' (for the circle charge) = 60' remaining).
This requires 2 feats, so level 8 without a racial feat. It requires a melee attacker without a bonus action doing something for them, which usually means a not super optimized one. At level 8 having spent 2 feats on this would mean 2 lost ASIs, so -2 attack and -2 damage per attack. It requires an allied spellcaster's concentration (or the character's concentration if they are a bladesinger) and a 3rd level spell. The only thing that could conceivably make this better than just attacking 3 times regularly with the +2 to hit and damage from 2 ASIs is the high amount of movement this grants. Mobility feat alone can let someone 'kite' a slow moving melee enemy. Double movement (you don't need to circle charge, or you could move away, on their turn they move forward, then you charge them then flee etc) lets you kite even very fast moving enemies. This Flash style hasted speedrunner thing is sort of interesting but it's not really a generic situation at all, and there are builds that do this kind of kiting thing better/more unfairly, usually using ranged weapons.
Rogues can be melee attackers, and they also don't get extra attack. It would seem on paper that there's more reason for them to take Charger. However rogues are often squishier than most melee attackers. Taking opportunity attacks to circle charge someone is worse for them than for many other classes, and Charger specifies melee attack, not allowing for a ranged option which rogues usually prefer.
Only When You're Dashing Anyways
Just like Great Weapon Master, Crossbow Expert, or Polearm Master, Charger is most effective if you're regularly fulfilling the trigger condition, and don't already have a comparable use for your bonus action.
For most characters, taking the attack action almost every turn is the default (and hopefully critting/killing in the process), which is why Great Weapon Master, Crossbow Expert, and Polearm Master are all such popular choices.
If you want to know if Charger is a good choice for your build, just ask yourself "How often am I Dashing in combat and also lacking a good use for my bonus action?" In most campaigns that's not often, but it is possible.
What is Charger's Niche?
It's incredibly rare to have a melee oriented build that can attack as a bonus action without attacking as an action as well.
Feats such as Polearm Master and Great Weapon Master require you to attack with your action to get (or potentially get) the bonus action attack. This is also true for similar things like Double Bladed Scimitar's bonus action attack.
Charger is best for characters who already take the Dash action regularly, not for players who are trying to replace Attack action with Dash + Bonus Action attack. It vastly outperforms an ASI in this case.
Starting Combat Strong
If you regularly begin combat from further away than your move speed and need to Dash into melee range to fill your combat role effectively, charger is effectively an extra attack. The first round of combat is often the most important, so going from 0-> 1 attack in the first round can be more important than going from 2 -> 3 attacks in rounds 2 and 3.
Chasing Mobile Bosses/Minibosses
If you often fight single enemies who are highly mobile, you may find yourself taking the Dash action more often than you'd like. For maximum damage output, you should have a backup ranged options like Javelins, Cantrips, etc. and avoid using the Dash action if at all possible.
However if damage is a secondary role you fill, and your primary role requires you to be up in enemies' faces, Charger lets you chase them down and smack them too.
Greg the paladin uses heavy armor, his saving throw boosting aura, and a sword + shield to fill the Defender role in his party (his goal is to be hard to kill and hard to ignore). His secondary goals are 1.) making sure his Rogue can trigger Sneak Attack by being within 5 feet of the main baddie every turn of every fight, and 2.) Dealing as much damage as he can while fulfilling the primary objectives.
The campaign is heavily centered around Dragons, who have very high movement speeds (even Young dragons have 80 ft fly speed), Blindsight at 30+ feet, high Perception, and are immediately hostile when they sense humanoids entering their lair. Initiative is usually rolled while Greg is more than 30 feet from his opponents.
His allies include a Wizard who regularly buffs him with Fly and likes to cast spells from max range, a bow wielding Ranger, and a skill monkey Rogue who also likes to snipe from long distance in combat. All 3 typically stay outside the max range of any dragon's breath weapon (Young Blue, Bronze, and Moonstone Dragons have 60 ft damaging line weapons, and the Moonstone Dragon Wyrmling even has a 90 ft cone for Dream Breath at CR 2!). Greg tried using a mount that the wizard cast Fly on, but it's just not durable enough to survive in melee with a dragon.
Greg took Sentinel at level 4 to make sure dragons have trouble getting past him to his squishy allies. Now if they want to get past him they have to spend their action to try to Shove him away instead of using Multiattack or Disengage, and then fly to his allies. Still, some dragons consider this worthwhile, and because his allies try to stay so far away and the dragon's move speed is so high, Greg often dashes mid-combat just to catch up. He's still performing his role adequately (any round a dragon shoves him they're not using a breath weapon!) but wants to actually get to proactively deal some damage in these fights.
Greg's Level 8 Choices
Great Weapon Master, Polearm Master, or an ASI would do nothing in tough fights since he's frequently not taking the attack action (and he's not willing to give up his shield anyways since he's tanking dragons all day and his main damage comes from Smite). In the fights he is taking the attack action repeatedly, his party is easily winning anyways.
Switching to a ranged weapon or cantrips is not an option, as his main value is keeping enemies from getting close to his allies in the first place, which is most effectively done with big smite Opportunity attacks that reduce their speed to 0.
Greg might consider Mounted Combatant so he can keep a mount like a Warhorse alive that the wizard can cast Fly on. No damage on successful DEX saves is great, and he can prevent it from being attacked. However many dragons can force saves other than DEX (Moonstone can put enemies to sleep on CON save). A Young Amethyst targets STR with its breath weapon, and deals average 18 force damage even on a successful save, just 1 point from Warhorse's max hp. Even with the investment, it's too likely the mount goes down to a single attack. If the campaign continued well past level 13 and Greg got a much more durable mount like Pegasus or Griffon from Find Greater Steed, this would probably be the best option (especially to free up his wizard's concentration), but Greg doesn't think the campaign will go that long.
Charger is the clear winner for Greg. It gives him an extra attack each round in the fights his party needs help the most, with some bonus damage thrown on top.