I can’t tell you how big of a problem this is for me when I’m trying to paint on a video game character. I absolutely love Mudbox, but it needs an option for painting only on selected polygons or else an option disallowing paint to affect hidden polys. Freezing should also have an option for affecting paint as well to help prevent accidental bleeding when you only want to paint on non-frozen surfaces. PLEASE add this as an option in an update sometime. I seriously want to use this thing in my workflow but it’s very difficult because of the lack of such features.

Other than that, Mudbox is a downright wonderful product.

yes marking faces for paintig would be a great feature…

i use uv tiles for masking faces i dont want to be painted…
with the up arrow key you are able to hide textures based on uv tiles…
http://www.youtube.com/watch?v=Ro_Ruhu-SGs

paint layer masks are also a great feature…

http://www.linkedin.com/pub/christoph-schaedl/6/558/73b