But if you ever get to the position where you buy the systems and maintain the networks and OS I think you would be better with Blender on linux machines. Its a much more affordable way to go. Considering you can buy or build systems for around $400.00 that run blender fine, why pay an additional $200 for a windows OS on top of that...but I dont know you or your systems, Im just throwing that out there. You can also set up a small render network with Blender. (Or a very large network for that matter)

If you are teaching people then you need to consider the future also. Blender is in the middle of a constant software lifecycle whereas Wings 3d seems to have become stagnant and Truespace I dont know much about, but I seriously question why they would all of a sudden give it away for free.

Blender development seems to have no end in sight, and more and more people are getting interested in it. Its very important that you pick software that has a healthy development cycle.

You get used to the interface, just like anything else.