I'd go for the RIA compact. As others have said, there are many choices in accessories to choose from in sights, grips, ammo and replacement parts.
I've had a CZ82 and still have a Russian Makarov, which the PA is patterned on(except I believe having an alum. frame?). Both of them are fine pistols, but the draw-backs, IMO are;
1 - 9x18 is an OK round, a little better than 380 but limited in ammo choices.
2 - CZ double stack gives alot of rounds but ends up feeling much larger than the Mak.
3 - Both the Mak and CZ are very limited in choices for grips and sights.
4 - Both are heavy, given the round they are based on.
5 - Neither one will conceal or carry any easier than the RIA will.
Now, if I didn't have the the Rock, I'd definately fall back to the PA63 or Makarov, if only because I feel is carried easier than the CZ.
YMMV