hehhe... good debate.....this is how i see it...
since most of the reply are mostly based on hware spec etc.. i'll point out my view from a different angle...

Android Vs IO4 = Democracy Vs Control Freak

Google says = "Evryone can do wat ever u want with your phone...no limitation.. we'll provide u a platform so evryone can play with it...no strings attach"

Apple says = "everyone must follow what we say... what we sell to you is what u'll get..dont change anything...if we say IP4 is cool, u say its cool....btw, put the rubber bumper around the phone to improve signal, dont touch it by any means... otherwise, just put the phone on the table, and use speaker phone instead... dont say we didnt warn you"

then a potential IP buyer ask Apple >> does that mean I can only use Itunes to work with my music collections? how am i supposed to share data with others? I can at least use Bluetooth, rite ? No?? or at least give us removable memory card.. battery ?? my own mp3 ringtone?? ayoo.. why this cannot, that cannot?? Android can do all that ma.. why cant you??

then with a robotic voice, Apple users report back to HQ : ok master.. if u say i cannot customise my homescreens, thats ok.. cos ur my master... ur always right... i don't need to share files between phones, even between other IPs out there....and i will always use Itunes.. and i will pay for all the app from appstore... i dont need variety in my life..

I nearly bought an IP before a friend of mine using Nexus told me bout android... what a saviour.. i never looked back ... IOS is soooo yesterday..
In my case, i dont like being told what i can or cannot do.. thats why i go for Android....thats the real discussion should be... not hardware comparison...
and it happens to be X10 is sooooo sexy (cosmetic wise), i chose X10 for my first android... some limitation are mainly OS related, which will be rectified with OS updates.. it might be late, but its just the matter of time....

after i was fiddling around with my friend IP4 for the whole day, it drained his battery out.. i must say, Ip4 has an edge design with its front n back glass cover, nice display and smaller screen....but it is soo fragile.. one drop could mean rm800 down the drain to replace the crack glass cover....
and the rubber bumper ruins it all... not to mention the flat surface.. my palm so reluctant to agree that holding an ip4 is comfortable...

nonetheless, there are lots of people who would still support Apple despite all the flaws and limitation.. maybe Apple figured out a way to convince people subconciously...buy me.. buy me....ehhe... expensive phones means the best phone... (yeah right)....