[basementjack]

I don't think you can go wrong with the 400.

Costco sells them, and they have a terrific return policy - I think I'd start with them and see how it goes.

Also Target.com sells them, and if you have a target credit card you probably get 10% off coupons from them in the mail all the time - so that makes the 400 $1350.

the difference between the two is lens throw range, contrast and brightness.
you either need the lens throw or not so thats no big deal.

Brightness is not an issue if you're in a dark room - and it's important to note that to get the brightness out of the 700, you've got to be in dynamic picture mode, with the lens at full wide angle. Most users will use theater black most of the time...

that leaves contrast, and while it's neat to be at 10:000:1, remember thats with the iris so thats full off/on contrast. In scene contrast is probably closer to 1500:1 - and I doubt that would be much different on the 400.