From what I have heard Rhino lining gets 'hairy' after repeated abuse, and fairly quickly, which causes undesirable drag.

Everything I have read, posted and inquired about over the phone seems to point at Coat-it as being the superior product...

One of the local/non-guide types on my Hohme river uses roofing tar and swears by it...

I'd never put that crap on my boat personally but I throw it out there as an example of the variety of opinions I have heard on this subject