Myasishchev Bison

I was reading some things about the Bison, and I got to wondering a few things about it.

What were its direct contemporaries? Victor, Valiant, Vulcan, B-47, B-52?

How many different variants were there?

Arthur I know you know some of this so I’ll be expecting some interesting info that I wouldn’t otherwise find just searching on the net. 🙂

Also, are any Bisons still flying (in their original guise or at VM-T Atlants) these days?