Kimber uses a unique mag. Para & Springfield take the same mags. Don't know about RIA.
I have Kimber BP Ultra Ten II, Kimber BP Pro II, Para P14, P13, & P10, and Springfield Ultra Compact (a Para P12 "clone").
All have had mag related problems, but function fine with factory ammo and good mags. Hopefully the AWB will sunset and good mags will become available again at reasonable prices.
Boths Kimbers and SA feed and function fine with my 200gr Lead SWC reloads. The P10 is useless with these, the P13 and P14 haven't been used in quite some time but I don't recall any problems with them and my reloads that weren't mag related.
Of all of the above, I like the Kimber BP Ultra Ten II the best. YMMV.
--wally.