I don't have one. Anything that's accessible, quick and consistent I suppose.
I feel like it's weird to have a favourite for something like this, because it's not really something people do for fun or because they like it so much. If they succeed in ctb I guess that somebody would have considered that their 'favourite' if they were still there to have that opinion. Can't imagine anyone having failed attempts and considering one of these a favourite even if it's the only one they somewhat experienced and would be able to have formed an opinion on.
I do get that I'm looking to much into such a simple question though, my bad