In reply to Mikkel:
> I want an ultra wide lens for my DSLR.
> Will the 2mm difference at the short end between these 2 lenses make much of a difference?
Yes and no. The issue is likely to be whether 8mm is more useful than 10mm. The latter already gives a pretty wide field of view with plenty of 'distortion'. I'm not sure more of the same is much 'better'. On the other hand, if you have the range, it doesn't mean you have to use it (how much self-deiscipline have you got?). Go play with one in a shop - only you can judge if it's what you want - but don't get wowwed by the novelty value of 8mm which might wear thin after a couple of 'rolls'.