[quote name='dmaul1114']Oops, yeah I forgot the device limitation as it's never been an issue for me.[/QUOTE]
Even if you forget to de-authorize a computer after you recycle/sell it, Apple CS can usually do it if you call them up. Just have your account info and security answers handy, plus a little time.
While it's a little bit of a pain to have digital copies across at least two distribution platforms, I think I prefer UltraViolet's system as opposed to iTunes. At first I thought UV was exclusively streaming but they offer an app that lets you download the movie. The FAQ actually doesn't specify a device limitation, just that 5 different accounts can share the same movie.