I agree with Sean's points above. This is a low production specialty product that has only been going for a few years. It doesn't use dealer networks, so it can keep the price down. It is factory-only, primarily via internet.
While it hasn't gotten many magazine riviews, It did get one earlier this year in Listener Magazine, that was fantastic. And all of the owner's reviews are glowing also.
I own a Teres Model 245, and I am very happy with it. I wouldn't trade it for the top of the line from any other TT maker, except maybe Walker or Rockport. I am very serious about my TT performance, and use only vinyl in my system, nothing else. This TT really gets it.
As far as your dealer goes, the "joke" is on him. A Teres TT will blow anything he's got right off the shelf. He can't sell one, because it's factory direct, so he makes disparaging remarks. This is a typical sales ploy, and he probably doesn't even know what a Teres is. Likely a shoe salesman, that got into audio(no slur to any shoe salesmen out there). But you don't have to know much about audio to put some stuff on your shelves and sell it to the general public. Good dealers know what they are talking about.
If you search Audiogon archives, AA archives, and maybe some other sites, you will read owner reports of this TT, and I have never read anything bad about this TT. I listen to one every day, and I have only accolades to report about it.
So it's not really a "mystery". It's only a great TT, that is factory-direct and reasonably priced, that alot of other TT makers and their dealers wish would go away.
If you want the very best sound for your money, and you can't spend $30k, the Teres is your table, my friend.