I gave up on Windows mobile with WM7. It has been too slow to market, has no application support and Microsoft honestly fashioned the phone after the failed Zune! I no longer deploy it unless asked to. I'm on a Droid device. The VPNs don't work, but everything else does. I can RDP through my TS Gateway to control all my servers. I run Touchdown for improved Exchange sync. I have a number of other little apps for personal things like listening to radio, etc.
My wife has an iPhone. Better designed than the Droid, in my humble opinion, but no available keyboard and no flash support. It's tough to RDP when half the screen is used by a virtual keyboard.
I also manage BlackBerry devices and BES for my company. They're OK, but they don't do much.
Sad to say, but Windows Mobile is dead. A least it brought us push synchronization for the good smart phones to use.
The new "Mango" handsets are going to be sweet and the OS is awesome. I have a Samsung Focus and love it.
Get on board with Android.
That "Mango" may be ripe, but it's full of worms.
I told you before that if the iPhone came to Verizon I'd leave my Windows phone in a heartbeat. Well it became available, I switched, and I don't regret it. I won't have a Mac in the office, don't have an iPad but I do love my iPhone...
I have a BlackBerry, a WP7, and an Android. Overall, the WP7 is the best -- particularly if you have a Zune subscription. I use it with either Bluetooth headphones or Bluetooth speakers for music. The e-mail experience is great, Netflix is nice, the Play To feature is unique, and the Panorama App is very cool. I develop apps for all three phone types and app development on the WP7 is the best experience.