I have a nelson on a dedicated caspian frame and it runs like a top. It does have issues when dirty trying to eject a dud, but that is usually after about 250 rounds. A quick run of a bore snake and it is fine. Only the Nelson mags will work, the ones brownells has will not work reliably. As for accuracy it is probably one of my most accurate 22's I have. Mostly shoot CCI standard velocity, but cheaper will function. Makes a great host also.
Now my buddy has one on a 2011 frame and it has issues. He swapped it over to a single stack and it runs fine.
We use them in local rimfire falling steel (RFS) matches and they are competitive.