630 is too big for my needs, but fits my big paws very well. 710, I only have a 154CM model, but wish I would have gone for the D2. It is my big weekday EDC (my small carry is usually a slippie or traditional lockback). I've never been a big fan of the Emerson designs, but I had a Benchmade CQC7 once, great knife, and I've heard only good things about them. If you really need a super beater and have big paws, go for the 630. If not, then go for the 710. The 710 is a better knife IMHO for my needs anyway. If you are looking at incorporating SD into your knife carry and know what you're doing, I would look at the 630, closed it is an impact tool.
Basically, what you need to tell us what you are going to use it for.