are the various license options for zbrush all commercial licenses?
also, zbrush works for sculptng models for maya and is much better than mudbox?
any feedback would be great.
There are both commercial and academic licenses.
If you are a student or faculty at an accredited school you can get reduced pricing for a non-commercial license. The resellers that provide academic licenses have their own heading at http://www.pixologic.com/resellers/.
If you don’t qualify for an academic license, then the only other option is the commercial license.
Most digital artists would agree that ZBrush as it is today is a better 3D sculpting package than mudbox.
In my experience ZBrush offers not only a superior tool set but Pixologic’s attitude towards software updates is unrivaled - every update (for licensed users) so far has been free of charge.
There are a few functions of mudbox that I would still like to see in ZBrush but not enough to make me change from this revolutionary application.
I could go on, but why don’t you just look at some of the most popular artwork here at ZBC and compare it to mudbox galleries and decide the potential for yourself.
And yes by all means can your work from ZBrush be used in Maya.
Hope this helps in your decision. 
Thanks heaps for the feedback it has helped me:)