I just got off the phone with revmax. I was interested in them because I'm broke right now and I need to get a cheap stall to complete my 4l80e swap. I asked about their stage 3 4l80e ($335 w/shipping) verter that they have listed on Ebay. THey said that particular one would burn up with the amount of power/weight I have within 6 months so they suggested I go with their level 5 Converter. I was intending to buy a cheapo verter till it burns out till I could afford a Circle D or a Yank but guess what? The guy says the Stage 5 is the same manufacturer of the Yank and that they are virtually identical.
Revmax stage 5=$725+$35 shipping
Yank =$900 to 925+shipping

Hmm, if the guy isn't "Yanking" my chain I think that's a pretty damn good deal. Plus they come with a 2 year warranty. Anybody else run these verters?