The pistol forum is pretty slow, and I need a rather quick answer- thought I will most likely get quite a few more experienced shooters looking here.

A local store has some South African 15 round Beretta mags for the 92FS, $29 a piece.

I know original mfg. mags are probably the best, but being from Ma, it's sometimes tough to convince mail order and web places that we can actually buy hi-caps from them.  CDNN investments has quite a few hi-cap mags, but give us Ma. residents a flat no to ordering from them, eventhough most of us are legally licenesed to have hi-caps.

Any advice or experience with these mags?

I have heard they are reliable, but I don't have any personal experience with them.  You might want to buy some and replace the follower with a factory Beretta and use a wolf spring also if they give you any trouble.  I think I saw an earlier thread that someone did this with some balky after market Beretta mags. They weren't SA though.  Good luck.