I'm in exactly the same boat
The Sony is quoted as doing UXGA for PC input which makes me want it more over the Sharp's XGA, I'm going to be running my PC's through mine (when I have enough cash to spare for it that is

).
I've seen both in action and had a full demo, I'd say the Sharp has just as good a picture as the Sony. The guy in the store wouldn't move them side by side for a proper comparison though, so I may be wrong

(the Sharp was in their Sharp
"cinema room" and the Sony was by the windows just sitting on a shelf in the "Sony" section

). The guy said the Sony was better though! Cheeky!
I checked out the Sony Centre too... I don't know how their DVD was hooked-up (S-Video the sales guy said

) but blacks were pretty grey and it was a bit blocky and pixelated (maybe it was their crappy low voltage lighting that was shinning above it?), fine at the other store though (who just had stretched analogue TV running through theirs

)...
The Sharp does do progressive scan (well it was in the set-up menu anyway and I asked the sales guy to make sure

).
The Sony has more inputs (always a bonus), but to be honest I didn't think much of the media/tuner box, my old 80's VCR is smaller!
You can download the manual for the Sharp
here
I'm going to give it a couple of months to see what happens with the prices. Nice thing too is the guy at the Sony Centre said he'd beat any like for like price I found (including Internet

), just I'd have to pay cash

(they've got it selling at £4,200 at the moment).