I don't recall a wheel from Rev called 'X'. You sure about that?
Rev wheels are made by Arospeed. They are typical aftermarket cast wheels that have to meet international quality standards like every other wheel in the world. (SFI, TUV, JWL/VIA, ISO9001, QS9000 you name it.)
I would just worry about checking on what kind of warranty the Rev lineup has. No wheel is indestructable and even the best forged wheels have faulted to heavy pot holes or minor collisions.
The Rev X (i.e. Rev model 10) are pretty light with a good price tag, I even considered them myself but in 17s you will need spacers for the front wheels.
As far as the quality, Evo77 lays it down pretty much...NO wheel is indestructible, I have Rev wheels myself and don't see any sign of crackin'