I don't think you can go wrong with an iPhone or an Android device. Obviously, if you decide to go down the iOS path you don't need any help, but if you're still considering Android, you should probably investigate these five phones:

http://gizmodo.com/5906041/five-best...es?tag=android

And remember, the Samsung Galaxy S III is being unveiled early next month.

Also, if you have any specific questions about the differences between iOS 5.1 and Android 4.0.4 (ICS), I'll try and answer them.

really thats how you loose credibility? hmmm..
people really cry down symbian but how many of you have used symbian recently? ive used symbian recently and i do really like it. its actually not a bad os. i mean personally for me the iphone os reminds me of a teenagers room where you just hang some posters on a wall (and call it an os)...the new belle os is quite nice and smooth...what are you going to argue now? nokia store doesnt have a gazillion apps? well surprize symbian actually doeesnt need a gazillion apps to do stuff as alot of base features of symbian comes out of the box... no need for plasters to cover inadequecies...plus with that (41)mp camera and pureview technology its a decent choice...oh and its just as fast as most of the devices out there....and yes i do still have an n900 and n8 own an n9 sold my ip4s (bought it t check out what the big hurrah was all about) and i will be getting the 808 as well...
if i had to choose os's in order of relevance it would be
maemo
android & meego
symbian
ios
BB
wp (wp really sucks to me..very boring os)

*end of rant*

HTC one is a quad core device, but as it has been pointed out the battery lasts about 16 hours or so... With great power comes great power consumption

And if your phone keeps dying out, i dont think it will do any business any good. I haven't heard much about galaxy S3 but I've tried out galaxy Nexus and really loved it(Even though I have an N9... I love my N9 too)

it seems to have just the right screen size. Multitasking I cannot comment on.

Probably not what you're looking for, but the physical keyboard has not been forgotten.

Hands-on with Kyocera Rise, an Android 4.0 smartphone with a QWERTY keyboard