I have one, the super-AMOLED screen is stunning and I am told wont be on any other brand of phones for 18 months or so. Not as many pixels as the new iphone4 but its much brighter, half an inch bigger and the colours are allot more vivid which imo makes it a better screen when you compare them side by side.
It's very fast too, i'm told the Samsung 1 GHz processor is quicker then the snapdraggon 1 GHz processor in the desire but I doubt there's much in it. The only down side is if your playing a game or something on it the battery will only last 4-5 hours but at least it can charge from any usb socket on a standard lead.
Some people say it feels a bit cheap as it is very light but again its down to your own preference. Personally I like how light and thin it is.
The camera is the best I've used on a phone and the HD video recording is great. The only thing missing is a flash. I have never liked to use the flash on any camera but they do make useful torches on a phone. The screen however is bright enough to use as a makeshift torch should you need to.
The amount of supported video file types is also very good and I have had no trouble playing back huge divx avi's, mp4's etc. Videos really do look good on the Super-AMOLED screen.