Im choosing the HOX or S3 simply because Samsung is and already has already taken too long to spill the beans on the S3, its like they are hiding nuclear weapons or something. And also its time for a new phone and I dont feel like waiting several more months for the S3 to be released. And the fact that it takes Samsung/At&t forever and a day to release updates to their phones. Another note I hate about Samsung is that they release multiple versions of their phones like the S2, S2 Skyrocket, Skyrocket HD, etc... lol
Edit: Im still using my old captivate simply because I wanted the S2 but then came the skyrocket and others then came news of the S3 so I couldnt choose until I saw the HOX at MWC then I played with it the other day in the local store and Im completely sold on it now.
Samsung Captivate: SLIM ICS 3.5
HTC One X: Pending Rom