I bought one when they first came out and now it's a safe queen.
The first time I IWB carried it, the magazine became disengaged at some point on a day in which I was more active than usual (going up and down a ladder on my house), partially dropping it from the mag well. This is because the mag release button is positioned high enough above the surface of the grip that body movement provided enough pressure to actuate it while holstered. It was also summertime and after a couple of weeks in my holster, I removed it one day and noticed a build up of red rust at the muzzle.
I don't like the fact that slide removal involves removing a pin I can lose. Not a fan of the obnoxious looking "shark fin" loaded chamber indicator. It is far less accurate than my two other sub-compact 9's, the S&W Shield and the Sig P365.
Worst of all is the fact it has a magazine disconnect. Mag disconnects may be fine for a range plinker, but having one on a handgun you may need to rely on to save your life is a really bad idea IMHO.
I know Ruger has made improvements to this design since I purchased mine, but they seriously dropped the ball in the one I own.