toughy. where did you find a cz 75b for under $500? they're closer to $700 now, which puts it in the price range of an sti spartan v instead of a rock island armory. this would make it a much harder decision. as you can see below, both made it into my top range gun category. if you can truly find a 75b for under $500, jump all over it. for carry purposes tho, i'd be leaning more towards the cz pcr or p-01. still holds 13 rounds, great ergos, but smaller grip and barrel for ease of concealment.
Favorite range gun for the money - CZ 75B or STI Spartan V 9mm
Go-to carry setup - Walther PPS or PPQ in FIST kydex holster 1AK
Favorite .22LR - Browning Buckmark
"A Sig is like a lightsaber - not as clumsy or random as a Glock."