If you have B+, then you'll get the GUI module for Bmax for free (or at least, so it seems), which means you can just do in Bmax what you could do in B+. So in all cases: get BMax and the GUI module.
Even games need a GUI, no so much for the game itself, but where are you going to edit maps and such?
Even games need a GUI, no so much for the game itself, but where are you going to edit maps and such?