I'm not convinced that the drain feed location or orientation makes any substantive difference in print washing - washing is a diffusion/exchange process, and as long as there aren't significant locations of poor exchange in the washer and the water temperature is adequate, I suspect the drain location makes no difference whatsoever. Cascade washers seem potentially useful for long printing days, but I can't imagine there's any difference in the actual efficacy of the wash.
Martin Reed's "Mysteries of the Vortex" is the most useful wash resource I am personally aware of.
Mysteries Of The Vortex (Part One) Articles
www.film-and-darkroom-user.org.uk
I can offer no feedback on Under Red Light washers specifically, but I think the options are more or less limited to them or Versalab for a new washer. The Under Red Light washers are certainly nicer looking, for what that's worth.