I've simultaneously decided I want to get into RBAs and that I want to build a bottom feeder. Now I have to make sure the former will work with the latter. I've heard great reviews on the R2 but it's a little outside my current budget. What I've seen cheap so far is the A7, Phoenix and Octopus anybody know how these would work for this application? Anything else I should look at in the $20 or less price range?