Go for Moi3D.
Its more intuitive and easier to learn.
Both are very similar but i find the new UI in Moi3D 5 superior in every way.

As for the budget the 400 USD would cover the expenses as Moi3D as for now is not very expensive.
The downside for both programs is that Nurbs-modelling takes a way, way long time to master.
But that is the nature of Nurbs.

Moi3D is very exact and precis.
I use it for modelling and injection moulding purposes.