I have a bunch of Glocks of various eras. Most are 17's and 26's, which are my favorite models.
I just sent a Gen 3 17 back to Glock last week with a broken rail. Its been my weekly practice gun, with a minimum of 300 rounds a week through it, for about the past 10 years or so now, and had just short of 148,000 rounds through it when the rail went. Prior to that, it had a trigger spring go at around 90,000 and one go at around 120,000. Other than that, just boringly reliable.
My one 26 is also a practice gun, and it had around 26,000 through it when I quit counting.
Most of what I have are Gen 3 guns, but I have a Gen 2, a number of Gen 4's, and just picked up a Gen 5 last week.
Of all the Glocks Ive owned, the very first one I bought, a Gen 1 17, was the only one that was a problem. It went back to Glock a number of times, and they never could figure it out. Other than that, and now this broken rail, they have been the only guns to have had a problem. And thats across about 30-35 guns in almost 40 years.
In general, they are like the Energizer Bunny and Timex all rolled into one, and just seem to run and run, and run, and with no drama. And no drama is very nice.
If I had to pick one Gen that had it about all right, it would be the Gen 3 RTF2 guns. Really dont care about the "gills", but the texture of the finish on the frames is about perfect, and the closest to stippling as youre going to get, without having to stipple them. I have two 17's with that finish, and they are the only Gen 3 Glocks I dont or havent stippled.
Gen 4 and 5 finishes arent bad, but could stand to be a bit more aggressive.
I really dont care about the finger grooves. My hand fits the guns with them, no problem, and I have no troubles holding onto the guns that dont. Its the finish I find to be more important.
The great thing about Glocks is, they are just so easy to get what you want, and often without having to get someone else to do it for you. All you really need to work on them, is a punch or armorers tool.
A soldering pen, if you want to stipple, and a sight tool, if youre changing out the factory sights. You dont really need the sight tool, but it does make things a lot easier.