I have used iPhones since 3Gs was introduced. (that's still the one I use) Never able to sort work email by sender in Exchange, only chronologically. As i need to review, file and dispense with hundreds of emails every couple of days (with spam filters running full tilt), not being able to sort by sender is a big bummer - its so much faster to get thru a large batch if you can sort by sender. Most of the new 'droid phones have a drop-up menu in exchange that has a "sort by" button which includes sort by sender. Therefor i will probably switch to a 'droid phone. UNLESS, i'm missing some menue or option somewhere that would allow me to sort by sender (maybe the new 4s? Doesnt look different, but i havent really used it)