Picked up one Friday, cleaned the bore and put 400 rounds of reloads thru it.
Good gun, I have a G22 RTF to compare against and do indeed like the Gen 4.
I had TRUGLO TFO's put on when I purchased it, got them for $100 installed.
The sights, reduced grip and new recoil spring worked together to make me a little more accurate and I am able to get back on target a little bit faster on double taps.
Not one hiccup with the 400 rounds and I used Gen3 and Gen4 mags.
I do not know how a rail mount device will work since it is a little thinner and the new (larger) mag release is great in my opinion.
A couple of things, the grip frame plugs will not fit the new grip. On the sight installation the front sight screw head had to be thinned down about .0015 to fit properly. Lack right now of aftermarket parts.
I gt it at Tennessee Gun Country thru the Glock Military/LEO program.
Gun $440
sights installed $100
OTD $604.84
The following ammo works for me, may not for you!
Ammo I put thru it;
Rainier plated hollow points 180gr, Win brass, 7.5gr Longshot, CCI SPP
Unk Plated hollow point 180gr, Win brass, 7.0gr Longshot, Magtech 1 1/2 SPP
Hornady 155gr HP/XTP, Rem brass, 8.0gr Longshot, Magtech 1 1/2 SPP
Magnus TC 180gr, Win brass, 7.0gr Longshot, Magtech 1 1/2 SPP
Magnus 165gr JHP, Win brass, 7.5gr Longshot, Magtech 1 1/2 SPP
Berry's plated round nose 180gr, Rem brass, 7.0gr Longshot, Magtech 1 1/2 SPP
Berry's plated round nose 180gr, Rem brass, 7.5gr Longshot, Magtech 1 1/2 SPP
Magnus 165gr JHP, 6.8gr Auto Comp, Rem brass, Magtech 1 1/2 SPP
I would not trade my Gen3 for a Gen4 but if you want one go for it or if looking I would go with a Gen4 over the Gen3.