Well I started Nicks link a little while ago, so here's my personal update :read: for what its worth (not much).
IMHO, the Alpine Butterfly is easy and foolproof and not open for debate as the best solution. That said, the cavers butterfly works fine as long as you ALWAYS ensure that something is loaded into its loop (eg its not used for isolating a rope rub), it has ease of rigging/adjustment argument.
I would say, obeying above rule, use either, (and Im happy to hang from either) unless you could be subject to outside scrutiny in case of accident, then it avoids discussion if you stick with the Alpine Butterfly, which is very firmly my preferred (only) choice when rigging and which personally I find easy to tie and undo. Others may (will) disagree, so good luck with whatever you choose