I have the RX and the Aria (as well as the RTS-III, AX, and S2). I much prefer the RX over the Aria for just about everything, but sometimes I want something small and the Aria is definitely small. I have the 25, it's my most-used Zeiss lens. I also have the 80-200 f4 which I like very much, as well as the 50 f1.7 and the huge 28-85. Zeiss lenses will definitely blow a large hole in your bank account, and while I'm not convinced they're actually worth it I'll never sell mine and plan to acquire at least a 100mm macro when finances improve.