Hey guys, anyone redeemed and own an Ultraviolet movie collection?

I've purchased a couple of movies on Blu-ray recently - one distributed by Warner Bros. and another from Roadshow. The Warner Bros. one asked me to visit Flixter.com/getuv to redeem my UV movie whilst the one from Roadshow gives me the option to choose a "redemption portal" - the options being Flixter, JB HiFi NOW Video and EZY Flix.tv.
Does it make a difference which "redemption portal" I choose? Does an Ultraviolet account link all these "redemption portals" together? I've read the FAQs and I don't think I've figured out everything - either that or I'm over thinking this! In the past I've always redeemed my movies in iTunes. With the introduction of UV I'm a little annoyed that I have to use another online service, but I admire that it's a service that's supposed to be platform agnostic.

Can anyone help?