Well, thanks for chiming in, dragonworks- I guess. Not flaming you, but given as you "would never buy one," it doesn't feel like you have really contributed too much, really. I don't know if they sell, either, and one funny thing about CL is the only penalty of asking exorbitant prices is your stuff never sells. Just checked ebay- no too many J12T's (tremolo and reverb) and J12R's (reverb only, but treble and bass knobs) represented, with prices from $194 to $450, and completed/sold ones going for almost as much ($250-350 range) as the vintage version. Mildly surprising. I do think this is an under-appreciated amp- close enough to the tube tone everyone expects but also unique and enough not like "what everybody expects."
The 60's vintage version has three knobs- volume, tone, only one tremolo knob, whereas the 90's has vol, tone, trem speed and depth ("intensity.") and reverb "dimension." As fruit as I am over tremolo, I won't buy a trem amp that has only one control; I think of tremolo as a big part of my personal "tone," and being able to control speed and depth is important to me, and having reverb available on-board is nice, too- therefore it is unlikely I'd buy the vintage model, as I see greatly reduced utility to it. I have greatly simplified my rig- guitar>tube amp w/ on-board trem and reverb>power-tube attenuator (built and installed one inside the amp, so no additional box to tote around) when I want dirt is all I need about 95% of the time, the other 5% I will make do.
Ah, but each unto his own- I'd been curious about them when they first were introduced, but didn't buy then, and then this one sorta dropped into my lap. Liked it enough that my SF Fender Deluxe Reverb went to Studio101NOLA's amp harem where it has well earned it's keep, and the Jet became my #1. More because I am 99% over my amp GAS than the possibility I won't like anything else as much, it may be the last one I buy, at least for a while. I (actually my son, DJ, owner of Studio101NOLA,) paid far less than the prices I am seeing them go for, so I am feeling lucky.
But would I sell it and buy something else? If it "only" brought $250, probably not- it's rare to get even a Peavey Delta Blues (had one before the DR) for that much, and there isn't a decent tube-driven Fender anywhere close to that or even the pie-in-the-sky $600 maximum apparent haul for this amp. If I could get $500-600 for this amp, I might be tempted to turn that into a DB and some spending money- sorta a toss-up, though. On one hand, I like the 15-watt early breakup and unique appearance of the Ampeg, on the other the possible greater reliability and more power (which can still be attenuated to less volume and more dirt) from the Peavey has it's appeal, too.
I was mostly wondering aloud, so please, dragon, don't be offended by what I said first in this reply. You don't say why you wouldn't buy one- perhaps you, too, own a DR, for instance. I can suggest that if you did live with a J12 for a while, you might come to like it.