I have an MR 80 and I have had several guests who sat in my living room while I was listening to it assume they were listening to a CD. It is exceptional.
I like the MR7083 and its siblings quite a bit - it probably doesn't get the attention it deserves. The only negative in my book is that the memory uses a big NiCd battery that's kinda failure prone, but they should still last about 8-10 years or so. This is a huge contrast to the MR80, which has all kinds of stuff that can fail, and the MR7083 also pretty much stays in perfect factory alignment, which the MR80 definately does not.
The nicest thing about the MR7083 is that its "manual" mode makes it a true analog tuner - the tuning varactors are then controlled by a simple precision multi-turn potentiometer and the tuning knob. You can go easily go between synthesized preset operation for convienence, and manual mode for precise tuning or DX'ing.
I honestly can't remember there being hardly any difference between the 7082 and the 7083. The 7084 and MR85 are digital-mode only, but all of these still use a high-quality tuner module that McIntosh designs and builds in-house, which is vastly superior in every way to the typical Mitsumi OEM modules found in the vast majority of everything else. The AM section is even decent - the MR85 and the 7084 (I think) can also use an special external AM antenna (with a 5-pin DIN connector) that continually tunes the antenna across the dial . . . and it works very well.