I currently have two G43's. My wife carries one made in Austria and a Georgia model is in my rotation. I bought the first one after shooting a buddy's 42. The 42 works as a pocket gun, the 43 is just slightly too big but conceals very nicely iwb. I much prefer a double stack compact, but sometimes you just have to have something that conceals better.
The good: My 43 runs, period. It's been 100% reliable. This summer I used it in a 2 day defensive pistol class, almost 1000 rnds. The only problem was mag capacity for practice drills. The short sight radius was of course less effective at longer ranges, but otherwise I couldn't have been happier with the gun. The entire class was run at a rapid pace, under pressure, outside in 100° sunshine. I use a talon rubber grip wrap and never had a problem maintaining my hold with sweaty hands.
The bad: I've had problems with slide corrosion on the GA manufactured guns. My first was replaced under warranty, and the warranty replacement started pitting after 4 months of daily carry. Both guns pitted where they come in contact with skin/sweat and a full guard holster would likely avoid the problem. Both guns were removed from the holster and wiped down daily, the replacement was oiled daily and still pitted. The Austrian 43 was carried until my wife took it with no sign of corrosion. I should have traded with her when I received the warranty gun, but I figured the first failure was a fluke. Not so much. Other than the corrosion, the GA slide finish has shown no signs of wear or damage. Glocks are ugly anyway and the rust shouldn't bother me for the intended purpose of this gun, but it does. I haven't contacted Glock regarding this gun but I will soon. Their customer service is flawless in my limited experience.
Sights: I use Ameriglo Hackathorns and love them. These are very similar to Trijicon HD's. Incidentally, all of the LEO and instructors ran Hackathorns on glocks in the class I took.The orange ring on the front sight was super easy to pick up quickly in daylight.
Mods: on our first one, I undercut the trigger guard and smoothed the oem trigger blade as my wife complained that it irritated her finger. I also slightly trimmed the front of the trigger safety as it doesn't sit flush when depressed. I also installed a ghost connector that reduced pull weight to 4lbs.
Second gun, just a talon wrap. It worked for me just the same as the gun with mods so I left it alone. The ghost connector has since been removed from the first gun as it didn't add to accuracy compared to the second gun. My wife has now adapted to the oem trigger when shooting the newer gun.
Alternatives we considered: Kahr- trigger reach too short, reliability/break in concerns
Ruger LC9s- too small/thin
Keltec whatever - tried at the range, very snappy, junky feel
Sig P938- safety difficult to manipulate for both of us
Shield- viable alternative, I could go either way on this one, the Performance Center gun is very nice and best bang for buck by far, will probably replace my 43 if no CZ single stack comes along
Rami- wanted this one to win out but it's just too big, still want one though