Not sure what it brings to the table beyond Deluxe Paint V? DPV was a bit slow on anything other than a 060 but it was great. What's the benefit of using Brilliance? I know it was used to do the graphics in Banshee so that's impressive.
The interface. Very fast even in HAM8 mode. HAM8 implementation is the best of any paint program. Hard pressed to pick it from 24 bit. Rock solid stability. Neither supported rtg though.