Mine arrived about a week ago now so I thought I would feed back my experience.
Like Shahmatt I retired my Orange SF/Blade to get this, and it is like chalk and cheese. This really flies. Apps like Chrome work really quickly and well, and its good to be able to play Temple Run! :-)
I managed to root it easily enough using the Oneclick route, so that was good news.
My build quality seems pretty good. I dont have a loose home key, mine fits perfectly. My only gripe is the difficulty i have in getting the battery cover off, the fit is very tight. I need a flat headed knife or similar to put in the gap and twist to open it. Fortunately, whilst I bought an extra battery and desktop charger, the battery is so large I've never felt the need to replace it mid day. I do like to pop in my work SIM in there at the weekend though so I can take calls, so simpler opening would be appreciated. I imagine it will loosen up over time.
Whilst on the subject of batteries, I tend to use the phone for its data rather than phone abilities, so when I use it I tend to hit it hard, but I think I'd struggle to see out the battery in a day. It seems to 'lose' about 10% in the first 10 minutes of the day then slow right down. Today I'm 8 hours in and 63% battery, and have been using it on and off all day for twitter, internet etc.
I'd read about vibrate being insanely loud. I don't find it too bad at all. If its in my pocket it's fine, if it is on the desk then sure you can hear it, but you will any phone on vibrate.
The camera boots up and snaps about 100 times faster than my Blade, and pic quality looks great, helped no doubt by a nice bright big screen!
The ICS is plain vanilla aside from a couple of apps which I have deleted with Titanium Backup, and nothing seems to have suffered.
It all seems to 'just work'. I'd love a CM Jelly Bean Rom to play with, and to have Nandroid back ups etc, but I'm happy with what I have for now.
I read someone who said they could not scroll easily. I don't have that problem, I can flick Tweetdeck and it go on for ages scrolling down. I haven't tweaked any settings, it just works OK for me as is.
Ther's my 2 cents for now! I'm really happy with it!