Well that's kinda up to you on that 1. I have had my G27 Gen 4 for about 3 weeks now and I love it.
I've never owned a Gen 3 G27 so I can't compare the 2.
I can say that with the +1 peirce extension is a must for me.
I think the felt recoil on the 27 is less than my 22.
It's a Glock... You'll love either one lol... Both of my guns are gen 4 but I grew up around gen 2 and 3 glocks and I love the gen 3s too. I prefer the grip on the gen 3 but I like the way the gen 4 shoots so that's something you're gonna have to decide for yourself...