Fidelity Research cartridges

Any FR cartridge experts out there? Raul? Dertonarm? Syntax?
I have had an FR-7 which I bought a while ago. I tried it ever so briefly when I got it on an arm I now recognize as not being able to handle that weight (close, but no cigar). I just now pulled it out for kicks and after getting it adjusted with the big counterweight, I am VERY pleasantly surprised. Actually, I'm feeling kind of bubbly. It does not dig out the utmost in detail, but it just sounds very right.

Are there any other FR carts out there which are real steals if still in good condition? I know the MC-702 and the FR-1Mk2 and Mk3f by name, with good reps being assigned to the Mk3 and the MC-702. Given that the MC-702 and the FR-7 look quite similar, and they were offered at about the same time, what is different? And is the FR-7 just an integrated headshell version of the FR-1Mk3?