Anyone have any thoughts or opinions on Milltek vs Racing Dynamics high flow cat?

At $600 I'd much rather do a racing dynamics HFC than a catless downpipe.

 

I did the Racing Dynamics High Flow Catted Downpipe and Love it...I did send it off to Swain Coating for the White Lightning Ceramic Thermo Coating to keep "the heat in"...costs only about $125 including shipping. It is a three step process (thick) and works!!!