The pros actually get paid half-way decently on the US version of the show. If Nicole Cutler's article on how the pros are paid is true, Mark Ballas (the pro who was raised in the UK) would have to be crazy to give up his spot on the US show to come dance for the British version.
Brian was not particularly well received by US audiences and wasn't asked back to the show. However, I'm wishing him best of luck on the UK version. He does have a lot of virtues in that he's a really good dancer and is quite a bit taller than most ballroom dancers. He just needs to tone things down so he doesn't come across fake. I bet anything he realizes that was something of an issue and won't be smiling quite so big while dancing this year. What he doesn't seem to realize is that his over-flattery of his partners can come across as smarmy.