Will do. First impressions coming up (it's only been a day)...
First of all, it feels really nice to hold. This is gonna sound stupid but it feels... classy. Luxurious. It is also without doubt the nicest looking phone i've ever seen. But of a fingerprint magnet though. It's pretty large, but the thinness negates that, it actually fits better into my pocket than the hero did. Phone seems quick and responsive, no noticable lag.
The camera is amazingly good for a phone, both stills and video, especially after coming from the hero's poor effort. HDMI out is a nice bonus feature. Screen is really nice too - viewing angles apparently arent as good as some phones, but i havent really noticed it being an issue myself. The colour tone is slightly yellow, which i've seen mentioned elsewhere, but i didnt actually notice it until i put it next to the hero,
The only thing really bugging me is the lack of root, which means i can't easily transfer all my apps+data over. Shouldnt be long coming though, people are already the bootloader using sony's portal. There are only 5 homescreens in sony's launcher which is a bit weird - will put launcherpro on it at some point once the novelty and glitz of the sony one wears off.
Battery life, i cant really say yet, as i havent actually left the thing charging long enough to get a full charge into the thing.
So far i'm really happy with it. In terms of raw capability (aside from the camera) i doubt it's much more impressive than a Desire. I also doubt it will hold up as well physically as my hero did - it's not a festival phone by any stretch of the imagination. But so far it's been a joy to use.
[edit] Update - 5 days in.
Battery life was abysmal for the first few days, was having to charge twice a day. However, after doing a full discharge/charge cycle it's behaving much better - getting a full days use out of it now. Nowhere near what i was getting out of my hero, but this is par for the course for the current gen of big screen, fast cpu phones.
Screen is truly amazing. You can use the phone outside in direct sunlight, something the hero couldnt do, and nor, i believe, can any of samsung's AMOLED phones. Big plus. However, i suspect the screen eats more battery than an AMOLED equivalent.
Also, the phone has now been rooted by those clever people over at xda. Another big, big plus.
Really suggest getting your hands on one before making your buying decision, everybody who has picked up mine has done the whole 'oooh, that's really nice' thing - the thinness and lightness is very impressive.