I suspect that some of those listed on A'gon might be there because it's a real pain to have to remove 10 screws any time you want to try tube rolling! I recently had to send my SWL 9.0 (Signature) back to Dan, as I thought it blew something in the rectified power supply. Fortunately, it was apparently just a bad Sovtek 5AR4, and Dan made sure everything was up to spec (superb customer service, BTW!). He sent it back to me with a Ruby 5AR4, and the music, soundstage, and detail are better than ever! I've also tried an (old) Mullard 5AR4, but the Ruby proved superior in every way! I'd also like to try some other 5687's, but don't relish taking the cover off yet again. I know Dan's busy, but maybe one day he'll design an upgrade cover for the SWL which allows easier tube rolling/replacement! That might make the SWL 9.0 more attractive (for the long haul). Regardless, IMHO, the tube-rectified SWL is an absolutely superb linestage, and mine won't be listed on A'gon anytime soon!