I never used the F1 Dark but got the classic F1 EE thats just copper. Comparing the two that I have, the F1 is slow and better suited for stuff with a cold bug. I think the F1 Dark had improved internals and it might be faster with good control. The venom came out years ago, it's two piece, works better for stuff thats full pot and faster than the F1. Other pots have been made which are much faster, but I've never used anything else.
It really depends on what you are going to bench and if you are going to use LN2 or Dry ice. For dry ice i'd pick the F1 since it's 1 piece and won't leak acetone.
I guess it really depends on what hardware you want to bench and which form of cooling you will use.