I started with Shadowrun 3, not Shadowrun 2, but many of the rules are pretty similar.
Shadowrun 5 is a lot simpler in many ways than the earlier Shadowruns. You don't track two armor pools, for instance. The dice process is easier, and my players found not having to deal with floating target numbers a lot more fluid.
On the other hand, Shadowrun tends to bloat. If you play 2nd, you'll never have to worry about technomancers, wireless hacking, wireless bonuses, and a whole host of things that got added after the fact. I don't think Mystic Adepts were even around back then (I believe they started in 3e with a supplement, but might be wrong), which probably makes the game a little more balanced and less confusing in terms of magic users. Likewise, 5th Edition has limits and the like that tend to make play a little more difficult to pick up than it is in the earlier games.
In short, there's not a real solid difference between the two; they've been almost entirely reworked, barring some of the style and terminology, and really resemble two different games entirely. As far as ease to learn, it's more about which you can teach best; whichever you are most familiar with and will have the best ability to explain will be the easiest to start play on. Personally, I lean a little toward 5th Edition, just because it feels a little more modular and because there's a little less per-person stuff to learn (unless people feel like making, say, a technomancer-cyborg-rigger, or a mystic-adept-decker-street-sam, but that's their fault), and because it has less awkwardly crazy stuff if the GM's not paying attention.