I've just been through this. I bought my Roku 3 in the US (a mistake perhaps). My PlexPass works fine with it (yay) and it has Amazon Cloud player and Amaxon Instant Video apps (yay) but they won't work with my Amazon.Co.UK prime account (boo). They kind of halfway get to registration and show up in the Amazon 'couldplayer.com' device lists but then they fail to authorise. Annoying. Its not insurmountable to overcome what I precume to be a geolock but it is an irritation. Oh and its playing through my Panasonic TV that I bought in the John Lewis Clearance because it said 'Viera' on it but doesnt turn out to have the 'Viera connect' software on it at all although it has an RJ45 for streamed freeview channels. I didnt appreciate the difference.