I have about 25,000 rounds apiece through both my 17 and my 34, and my 17 feels just a bit quicker on target for me.
Having all the Glock frame sizes in both 9mm and .45, I find myself always going back to my 17, it simply works for me, and it is the one I shoot the best.
Both are great pistols and you won't go wrong with either, if the $ are there get both, as a spare match gun is always a good idea.