My wife has the iphone4 - the desire beats the iPhone not by much but still its better - its faster in getting webpages displayed, it feels better not as big as the iPhone.
Android rocks, no itunes (fucking shit) that rocks, screen is bigger, screen looks crisper, the photos look crisper on the desire.
Never had a smartphone, I am not a techboy that needs always the latest gadget, but I get it now its pretty cool.