Weather-wise its been plenty bright here since yesterday, I've found the sunlight performance really good, basically equivalent to regular LCD as far as I can tell.
Shame about the pentile though, I definitely notice the difference - if there are others here who find pentile displays quite noticeably less clear than others I'd suggest taking a look at a Galaxy S before committing. Its not too much of a biggy for me, for the other display characteristics I'll live with it, but your mileage may vary.
The loudspeaker seems decent enough, the criticisms seem a little over the top to me.
The build quality is fine, its light and plastic construction, which doesn't give a particularly favorable impression, but its solid and nothing creaks. I think I saw one person suggesting its build quality was better than the Desire, but that seems delusional to me.
Unconverted video looks great, plays perfect, quite nice via TV-Out cable too (excellent portable media player). Music quality is simply top-notch, and the music player is the best I've seen yet on an Android device. I find the scanning for media files very slow on my 32GB card, the Desire was very quick to index everything, presumably on the basis of only looking for new stuff once the initial search was done, whereas the Galaxy S seems to build the index from the ground up every time.
Connecting to Samsung Kies software is a PITA. Got it working by going to Settings-->About Phone-->USB Settings and choosing "Ask on Connection". Rather non-intuitive place to have that particular setting if you ask me.
Reception wise the phone seems very good, I'm getting by far the best 3G speeds in my home that I've ever had.
I wish I could say more about the phone, but unfortunately my Google account seems to be one of those affected by some mystery issue that prevents any download from the marketplace succeeding, which is proving a significant downer.