Dire Wolf is the better option here (usually)
Compared to the Crag Cat, the Dire Wolf has three more hit points and one higher armor class. This makes it (marginally) more survivable; I'd expect to survive one extra attack.
If I recall correctly, "combat efficacy" is measured in three-round combats, so I'll use that as my metric.
In the likely event that you're in melee along side someone else, the Dire Wolf is going to have advantage on all their attacks (with the added bonus of possibly causing the prone condition); whereas the Crag Cat can only prone on a "charge" and doesn't get extra advantage options.
Since they have equal to-hit bonuses, I'll just talk about absolute damage.
The Dire Wolf gets three attacks with Advantage for an average 32.25 damage over three rounds.
The Crag Cat depends on whether or not the pounce is successful.
Pounce Failed: 7,8,8 damage, for an average of 24.15 damage over three rounds.
Succeeding on the pounce grants an average extra 8.78 damage so that the total is 32.93 (barely higher than our Dire Wolf).
If you're willing to soak up opportunity attacks from movement, then you can bring this total up considerably by running 20 feet away and back in every round.
Unusually, use the Crag Cat against casters.
Spell turning is really powerful; obviously it only comes into play against casters. If you can access both, and you come across a wizard, it might be worth morphing into Crag Cat mode.