Your question doesn't make sense or the poll mixes two or three questions?

Anyway, note that the second P in MapPoint is capitalized, also the I in MapInfo, also all of ESRI should be capitalized.

My own vote is that they should all be easy to use with c#.

For a fleet tracking solution as you describe, with MapPoint you may need to get a Fleet license which is $750 (instead of the normal retail license) and available through MapPoint ISV-R providers and also through MS volume licensing.

good luck!
Eric