Not much difference in the heat wraps that i can see--but the best way to keep them clean is to spray the wrap with something like
THERMO-TEC High Heat Wrap Coating: Black It is available in black or silver. It tightens the wrap and allows water and oil to bead off. On our project bikes, the painted section lasted longer and looked better.
ThermotecInstall the wrap wet, let it dry in the sun and then paint the wrap on the pipe.
-M