Guessing no contest between the Shackleton and...
http://en.wikipedia.org/wiki/Tupolev_Tu-95 ...
How did/does the Nimrod hold up 
No comparison Shack V Bear (Tu -142 maritime version), they were turbo-prop and operated at similar heights to the Nimrod. I did see a few from the Nimrod, and we would give each other a wave.
Having seen the inside of Russian military a/c I prefer the Nimrod, which, based on the Comet 4, was a nice flight deck for the crew, most of whom converted from Shacks, albeit very old fashioned in modern terms. I spent 7 years on the Nimrod MR1, four years of which as a member of the air display crew, fortunately with excellent pilots, and always felt very comfortable with its performance. For a display, we would fly with a minimum crew, minimum fuel and no bomb bay stores, and therefore at these very light weights, the a/c performance was stunning.
If required we carried these for use against enemy subs.
http://en.wikipedia.org/wiki/B57_nuclear_bomb