Its the same thing that makes AP, TEC and Tak special. There are people who love them and swear by one brand or the other. With AP the limited number made and the wait time make them more sought after.
This essay by Thomas is a good read
http://tmboptical.com/itemsGrid.asp?cat_id=28
and a more complete version
http://geogdata.csun.edu/~voltaire/tmb/tmb1.html
Roland, Thomas and Yuri have made some excellent scopes that have been proven performers. They do differ in there philosophy of design. But the also have a great admiration and respect for each others work. This perhaps is the most special thing, and I think the Essay by Thomas speaks volumes about this respect. I have had the pleasure to see through my friends AP and let me tell you that its awesome, textbook perfect pinpoint stars on a very black background with not even a hint of color. Now another friend has the new GT AP and I cant wait to look through it.
These scopes are desired by many and that makes them special. I would love to own any hand crafted scope from these three masters. But i think i will be saving a long time before i can afford one.
Also look at the images posted by forum member Dietmar. He uses two TMB telescopes one is a folded 8". I think his images might ilusstrate more as to why these scopes have a special status.
Also consider these by Roland.
http://geogdata.csun.edu/~voltaire/roland/
Regards
Fahim