
Ironically windows mobile is the most "open" platform today. If you have an HTC device, going to xda-developers.com can get you a 6.5 ROM port for nearly any recent model. I can't install any software I want on a iPhone without dealing with app store, not sure what BB development environment setup looks like, Android will eventually garner more development support, but right now, with Visual Studio and
Windows Mobile 7 is going to require new hardware (fast processors, multi-touch etc.). The recently announced HTC Leo will be one of the first devices on the market that will support 7 out of the box.
I am not a "business user" but I did an extensive bake off for my personal needs of the winmo devices vs the iPhone. As hard as it was for this Mac and Unix user to accept, the winmo platform best fit my needs. My Tilt running a 6.5 rom will be replaced this week with a Tilt2 (aka TouchPro2) when AT&T releases them on the 8th.
The easiest way to figure the cost of living is to take your income and add ten percent.