Who is the best MDM vendor?

If you are just deploying iOS devices I would look at keeping it in house with the configuration profiles. You can use Apples Volume Purchasing Program (VPP) if you are looking to do paid app distrubition. MDM vendors that I've looked at (after looking at the Gartner report) were Airwatch, MobileIron, Zenprise and we ultimately chose Zenprise. All the MDM vendors typically are on the same playing field with iOS since Apple limits management configuration based on their available APIs. If you are looking to support RIM, Android, etc most of the MDMs will also support that as well.

It has a great deal to do with your environment. Some people can use the functionality of Lion Server and it will do everything they need. You might check out this link if you haven't already

http://www.apple.com/iphone/business/integration/mdm/

some of the ones I've heard mentioned are Good, AirWatch, Mobile Iron..but it depends completely upon your environment and security requirements. You might also check the Gartner reports...your Apple Rep can also give further advice...

iOS is a truly level playing field, and tools like Sybase Afaria, MobileIron, Airwatch all function very similarly on that platform. Their true power comes in supporting a heterogeneous environment as found in many enterprises.

If you only have iOS, then compare on price. If you'll need to manage Android, WinMobile, RIM, etc., then the industry leader right now is Afaria.

-Paul-

There was a critical capabilities report done recently by Gartner that was very helpful. They looked at 13 vendors and rated each by critical capabilities. The more well known vendors faired well but there are a couple less well known like Zenprise that should definitely be looked at.