Looks like a viable alternative to the Sigma 70-200 and the Nikon 80-200mm.
Think it's being reviewed in the next Photography Monthly mag...
Toguko, I'd expect the Canon /4 IS would be a better lens for someone who's shooting a lot of low lght stuff, as you'll get and extra two stops or so out of the IS system, which would trump the f/2,8 aperture of the Tamron. Still, I think the Tamron is £650 and that's cheaper than the Canon.