Mine has been flawless so far. Purchased last Labor Day from Plainfield Shooting Supplies, it has just over 4000 rounds downrange as of yesterday morning 06/14/2011. Mostly Federal Champion 180gr. JHP but also WWB 165gr and UMC 180gr. FMJ. I have also fired a little over 100 rounds of my carry ammunition Speer Gold Dot 180gr JHP. I have not experienced a single hiccup of any kind so far. My Gen.4 G22 has been absolutely flawless. Serial # PLSxxx test fired on 04/14/2010.
I bought a G23 (not G22) in January of this year and like it a lot--just like my other three Glocks (21, 27, and 30).
The only disappointment was the magazine release, which I thought would allow a mag to be dropped without repositioning the thumb or having to install an extended release.
The mag. release is so flush with the frame that I had to reposition my thumb to the very front edge to make it work, and there are no extended G4 mag. releases "out there" yet.
So, I made my own--took out the mag. release, built up a dam of little caulking strips, filled it with epoxy, let it cure, filed and sanded to shape, and then a few strokes with a black Sharpie pen matched the color perfectly. Works like a charm!
I own a Gen4 G23 & Gen4 G27. We currently have two Gen4 G23's and two Gen4 G22's in for T&E. Each of the T&E guns have over 2000 rounds through them and they've run very well with a variety of ammunition. I like the smaller frame (without backstraps) and the ambi mag release option. The trigger feels a bit different than the Gen3 pistols but I like it, it feels more crisp to me and once cleaned up it gets really nice.
Its was the first glock I ever shot (pretty sure) and I hated glocks...and i fell in love. It shot great, it was comfortable, I think the trigger had a 3 lb connector, it was short easy pull and felt great. It changed my mind about glocks and I went and bought a g17 later on. So yes as a former glock hater I highly recommend the Gen 4 g22, and any glock for that matter. I have read posts about QC issues with Gen 4's and apparently glock is using MIM extractors now. Take that for what its worth.
Edit: like another Guy said, the magazine release is larger but I didn't like it because I couldnt feel it (I'm a lefty), the Gen 3 mag release is superior imo
I love mine, done a few FNS with it, done several classes and shot USPSA for most of this year with it. Mine has had a little over 2000 rounds down range with 0 problems.
I've shot everything from my USPSA round, Fed Champ 180gr to the Blazer 155 crap! It easts it all, I even borrowed an extended mag at a training session that had never been in it and it ran flawless.
I can't think of any better or more reliable handgun platform in the .40 that has as little recoil, it's fast back on the sights for follow up shots.