I am a fan do to the simplicity if them and the grip. The Gen3 is nice but the Gen2 is awesome! I have shot a Gen4 and didn't really care for the grip.
I just like 15+1 rounds of 10mm in my holster. If it weren't for that I don't think I would have bought a Glock. Now that I have I like it, not love it, but it's a really good reliable weapon.