What is the best Reel To Reel machine ever built?


Everyone who has listened to master tapes or dubs knows about the well balanced sound they provide. But it is also important to have a fine tape recorder or playing machine to enjoy the tapes' qualities in a good system.
Maybe my question was raised once before but the relevance of the topic is now greater as the tapes are back to more and more audiophile friends, especially those who are owning excellent phono chains.

I have seen many big & professional machines being recently offered and sold on e-bay, Audiogon and other platforms and I am discussing within a small group which machine is really the "holy grail" among the R2Rs. So why not here. I am interested in findings.
thuchan
Mark Levinison’s John Curl Modified Studer
30 inches per sec speed
2 inch, two track tape
Huge stand!

Will never be beat!
Heard it play back 2nd generation Levinson Jazz tapes.
No better sound IMO!
I remember levinson building maybe modifying is more accurate a half track 1/4 inch tape deck back in late 79 or 80, but can't remember what is was based on. I remember trying to find one to listen too.  No one had one.
Can't for the life of me remember what it was based on? ReVox or maybe TEAC? I have the brochure somewhere. 
My Teac A 6300 (I thought) was the best sounding R2R I'd heard until I got my Tandberg TD20 SE - by far the best sounding reel to reel I've ever had or heard over Tascam, Teac, Sony, Revox, Realistic, Akai I think I've had them all at some point, at least in the Mid-Fi non professional class however running it through my Krell KRC-3 Preamp, Krell KSA 250 into the Thiel CS5i's has a lot to do with it but as a source the Tandberg is up there with my Meridian CD player and Linn / Dynavector and one of the best sources in it's own way - maybe a better question is what is the best sounding reel to reel you've heard and list your associated equipment used with the unit?
Atmasphere, since you have some very good R2R's have you ever tried to contact a major orchestra like say the Cleveland Orchestra, one of the worlds greatest to capture them on tape?  I am sure the records would sell as audiophiles know who the Cleveland Orchestra is all over the world.