It's worth noting that the 3d browser shouldn't initialize until it is clicked on. Otherwise the WAYWO thread would quickly succumb to a sluggish demise on some folks' connections lol.
Mudboxs painting is amazing, when it works. Try taking a low poly like MoP's Goblin sdk and painting it in Mudbox, the limitations become apparent very quickly.
Just turn on area shadows quickly in the light, and tweak the settings a bit, and even that simple addition of shadows will bring this more alive. I'm loving it so far.