Some people use the G34 because it is a lot easier to make major then with a G17 because of the longer barrel. just like sweetback said. KC uses a G34. Again like the others said, the longer slide will decrease your cycle rate and slow down your transition speed a hair. Would you be able to tell the difference, I don't know. in the STI area, they are going shorter for lighter weight and faster movement, but they are mostly shooting 38sc which is a lot easier to make PF then 9 Major. But the most important thing is FEEL. Every gun will feel different to you in how it feels and the way it shoots. The gun when shot will give you feedback and you will know if you will like it or not. I have both a G22 and G35 as my Open guns. I like the G22 better because it feels better to me when I shoot it. Again, that is all shooter preference. Use what feels better to you.