Well, marks are most useful in unupped tourneys, so marks of the elements most commonly chosen in that environment are going to be the best ones. I think I'd be pretty tempted by a darkness mark first; it's a strong element, and probably the best monodeck. I might take a time one first, just because my fg/arena deck is mark of time.
I played a few tournaments back in april (when I was unemployed and had the time!) and at the time I wanted to pick gravity nymph if I won, because it's the best nymph. (I never did win, got to the quarterfinals twice and lost in round 1 twice) However, at that time I think I only had one red nymph and no others, so nymphs were more attractive than marks. Now I have I think 8 nymphs and while I still don't have that precious gravity nymph, I'd take a mark instead because they are impossible to get in any other way, whereas nymphs are just mostly impossible to get, and I know I'll get the ones I want eventually from the oracle.
