I have gone from 3gs to the Desire.
My thoughts are the iPhone just works out the box and you need to fiddle with droid to get the best of it, but I like that sort of thing being a techie
The market place needs a bit of work, but no where near as cluttered as Appstore, but i do like the whole get an app from a QR barcode that is very cool.
It takes a bit of getting use to from the move, I am using the default keyboard and I find its on bar with the iphones, but the numbers button is the bottom right so catch that on occasion.
I like the ease of customisation, I can put what apps/widgets where I want not where Apple want me to.
I find it much faster than the iphone, but then the 3gs is what nearly 12 months old?
It is early days yet for me with android and I am getting use to it. Music management is what the iphone did very well, may or may not like itunes, but that system worked really well, but then on the flip side I can now just drag the music from my folder to the SD card, so really its all swings and rounder-bouts.
@Khaaan - Had a look in networks and only have normal o2 in there, but I still get data on it, will do a speedtest in work where I get H or use to and see what happens
Kimbie