I actually passed those in my searching, at least the 2 player auction. That was at the beginning of my search, so I have a better idea of prices now than then. And per your advice I re-looked them up, and am seriously considering them. The guy is apparently doing a couple auctions, one where I can get 4 for $25 shipped, which is good. =)
I'm doing a 4 player panel, so the R/B/G/Y color scheme was appealing as well for the happ ultimate. My wife is helping me design this (she's a graphics designer), so I'll have to run the color scheme change past her, but I don't think that would be a problem--changing the sticks alone probably won't be a big deal.
I should mention some of the games I'm planning on playing with some regularity are gauntlet and rampage, along with many of the fighting games. And some fighters like raiden and rtype. Sounds like these will fit those nicely. I'll be adding (I hope) a 4-way joystick for some of the "simpler" games as well, so I don't think those will factor much into this specific decision.
Thanks for the help, I appreciate it.
Anyone else have any opinions before I go out and buy something?

Oh, and cameron, refine your search to using titles and descriptions next time. Here's a link:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3254677908&category=13718 --Jeremy