i had a similar dilemma last week.
after looking at each of the phones and really scrutinising each one i opted for the Palm Pre.
The build quality of the Palms in my opinion is not bad at all feels very strong and sturdy IMO. I have has no problems with wobbly screens or loose backs etc.
The OS is brilliant and the phone runs very quickly and efficiently all the time.
Camera is vey good, youtube player is fantastic as is playback quality.
check out chrisblinkhorn 87 on youtube for my unboxing, i have done a first impressions video and uploaded it but it is yet to show up in the searches but im sure it will at some point today.
any other questions you have on the Palm Pre ask away and i will do my best to answer them for you.