Asking which tow bar is better (between Roadmaster and Blue-Ox) is like asking which is better: Ford or Chevrolet. There are pluses and minuses on each. I chose the Blue-Ox simply because I like the looks on my toad when it is disconnected. Every Roadmaster hookup I see on a toad has the hookup mechanism clearly showing. The Blue-Ox is basically invisible until you put in the actual hitch attachment posts.
If you have a really heavy toad, I think you are limited to the Roadmaster. Here again, this is a personal choice. I don't see the benefit of dragging a heavy vehicle, but some do.
My personal opinion is that you cannot go wrong with either a Roadmaster or Blue-Ox. It just depends on which hitch appearance you like and how much your toad weighs.
2003 Beaver Patriot
2014 Honda CRV Toad