Some things to consider if you haven't bought it already. I don't know if this is an issue with the newer 17L's or the 34's. But I have an older G17L and because of the large whole milled out of the top of the slide, you will have problems putting anything other than stock front sights on it. The front sight of any of the aftermarket sight makers is too long at the base and it hangs over into the milled hole. It looks goofy as hell and I think it causes the front sight to come loose, even with loctite, because it lacks complete support. I wound up getting a set of the Dave Sevigny sights and they are better than the ones I had on their before but they still hang over a bit. I haven't had a problem with these coming loose so far.
The other thing to consider, if you plan on doing competition shooting with it eventually. There is or are a couple shooting venues, where your gun has to fit inside of a box to qualify. The G17L's are too long to fit in the box, that is why they came out with the current longslides. They are about an inch shorter so they will fit in the box.
This is what it looks like with that sight hanging over