I have both a Shield 9 and a .22 compact. They are very similar in size (one of my galco holsters actually fits either one well).
I've had ammo issues with Federal champion / Lightning and American Eagle, but CCI SV, Minimags, Rem Golden Bullet, Rem Thunderbolt, Blazer, and some Winchesters (not all) have worked great.
At 5000 rounds it had to have the takedown lever replaced, but otherwise is original equipment / springs.
Yes, the rear sights were off out of the box, but they do provide the correct hex wrench to adjust. They do drift on occasion, but it hasn't been an issue.
Extra mags had been an issue, but I just a week or so ago found them on Midway at what worked out to be a better price after new customer / shipping promos were added.
I would not hesitate to buy another one if the need arose.