I bought my G17 back in the 90's. I immediately fell in love with it. It's just so damn reliable. It has at least 10,000 rounds through - never a misfire (factory ammo, though - no reloads, if that matters). It shoots tight @ 25 yds. Well, at least, I do, but I think the gun helps. I've carried it in a shoulder holster (under a sportscoat for work) & holstered inside the belt. It conceals well enough that my wife can't tell until she comes in close for a hug.
Having said all that, as was pointed out earlier, if Glock is having issues with the Gen4, I'd reserve my endorsement of the newer models.
Would you consider buying an older model used? Does anybody have a reason not to buy an older, used G17 if you could test fire 50 -100 rds.? Assuming it worked, of course.