The AE700 appears to be a fantastic projector for the money and has a much higher resolution than the 4805. In one review I read, the reviewer said he was 12 inches from the screen and still couldn't see any pixelation !!!
I think the contrast on the 4805 would beat the AE700 nd the processing may be a little better but I haven't seen the AE700 in action so I'm just going on what I've read. Also consider the new Sony HS50 that is due for release within the next month. High def Widescreen LCD with a massive 6000:1 contrast ratio for around £1800!!
At the end of the day, any of these and also the Sanyo Z3 are superb projectors for the money and which ever one you choose, I'm sure you'll be very happy with your purchase. The only problem with some High Def LCD projectors in the price range is a somewhat "artificial" look to the picture, a bit like the early Plasma screens looked. The edges are jagged and the picture in general looks "processed". This is where the 4805 scores highly with it's DCDi by Faroudja which effectively smooths out jagged edges and gives a much more natural look. Of course I'm biased as I own a 4805, so the best advice is find a stockist who has a few of these models and audition them. Failing that ,
www.projectorcentral.com has a wealth of useful information and reviews on all projectors.
Happy hunting !