I've got about 3500 rounds thru mine. I bought it just because the design was so neat, and even though I don't plan on getting any conversion kits for it, if the price was right I might pick up a 45acp top end.
I haven't had any issues after the first 50 rounds. I did have two failures in the first 50, one stovepipe, the other was a ftrb. After that, no problems. And I've given it a workout, not cleaning or lubing for about 1000 rounds over a 3 week period, and still not having any issues.
The magazines when first released by mec-gar had 15 round springs in them, Sig replaced mine with 16 round magazines. The one that came with it and 2 of the 5 I bought from CDNN were 15 rounders and 3 were 16 rounders. The 15 round ones would absolutely not fit 16. They weren't too tight or too hard to get into it, there just wasn't room due to spring bind.
The trigger is an incredibly smooth 5.5lbs and feels like a nice revolver. If you can shoot a double action revolver well, you won't have any issues learning this trigger at all.
Fit and finish is great but it's really only the top end that has a finish as the grip module is molded. There is zero play in the slide.
Since the firing control mechanism removes from the frame, stripping and cleaning is fast and easy.
I usually won't buy a new model gun, but I found myself well-enough impressed that I bought it more or less as an impulse buy. I haven't regretted it for a minute.