It's a very similar device. I can give you a quick run down of my thoughts:Starting to consider the 710 very strongly now. Can get a 12 month deal with 500MB, 300mins and unlimited texts for £17pm (retention and quidco cashback).
Same deal as what i was looking at for the 800 but that would have been a 24 month contract.
Just waiting for some user reviews of the 710.
It's a very similar device. I can give you a quick run down of my thoughts:
Thanks bud. I had similar thoughts. Do you know if the battery is the same? If so will the different screen lead to longer battery life?
Part of my thinking is that these are Nokias first WP devices and there could be some more killer phones coming out in about a years time for WP8 - so i don't really want a 24 month contract.
Going with the 710 allows me to get a 12 month contract. The main downside for me is that the 800 looks stunning, while the 710 is pretty run of the mill.

ooh is it glossy?!
That does look good. But it'll look horrible after a few weeks.
It's glossy, nothing can get through to the colour.
it doesn't need to, it can still tint the gloss. all white products look gruby after a while. its just the way it is and for that reason i avoid them. made a mistake getting white ipad.
They are well looked after though...