IMO, Sunn's have been way under-valued for along time, and are finally getting their due. A vintage American, handbuilt point-to-point tube amp that is built this well and sounds as great as they do (they are the best, in my opinion) is a valuable thing to behold. I have sold three mint 190B's on ebay for $750 to $1000.00 in the last year, and some may say that is WAY too much $ for them, however, keep in mind that they were all 100% original, in mint condition, with NOS GE or Tung-Sol 6550 output tubes and worked perfect. Look at the prices that the "boutique" companies charge for an 80 watt point-to-point amp with all American components and it indicates what a value they are even at my (high) prices. And everyone that has purchased one from me has praised the amp that they received.
Right now, everything on ebay (and the rest of the USA) is very soft so its a buyer's market. If you've been "jonesing" for a vintage Sunn, now would be a good time to acquire one.
Lately, I have been selling alot of ebay gear overseas (Europe) since the dollar is worth so little right now, but once the economy picks up again (whenever that may be), I would expect Sunn amps to pick up where they left off and continue to appreciate in value. Quality is quality and that will never change.
If you look at the prices of a vintage Fender Deluxe Reverb or a Marshall Plexi, they are still quite high. To me, they are way over-priced, and have been for along time. IMO, its about time us Sunn guys got a little respect since I prefer them over than any other bass amp---ever, and always will. I am in no way trying to inflate the value of these amps, but rahter just selling them for what I believe that they are worth (and I actually think that they are worth more than what I ask for them). And if one of them doesn't end up selling, I have no problem keeping it, as it wouldn't be the first time that i've regretted selling one of my Sunns for any price in the past.
---johnk