As the owner of dozens of high quality tuners over the past few decades, including a Marantz 10B with the broadcast monitor faceplace, I can say the the McIntosh MR-65B is in most respects on par with the 10B sonically, even though it's circuit topology is less sophisticated.
The MR-65B is a beautifully made, great sounding and looking tuner for a very reasonable price. I paid $360 for a very nice one on Ebay a short while back, and $610 for an even nicer (near mint) one with the beautiful walnut cabinet a few months earlier -- both of which I plan to keep for sometime.
From what I can see, the MR-65B, 67 and 71 are all very similar in their design topology, and offer a similar sonic signature. They are all quality classics to be treasured and enjoyed by those who appreciate vintage hi-fi gear and the rich sound that vacuum tubes provide.
JimmyBlues