This should have had more options, but I'm going for Dirtie mainly on the fact that I have yet to see Wiggins et al playing rocket speed yo-yo cycling up vertical walls for fun vs. Rasmussen.
I have huge huge doubts of them, but as yet none of them have been implicated in Puerto and had handy government backing out of it, been banned from GTs, had wins stripped, been banned, had plasticizers in samples, etc.
I'm not saying it's not something in their future, but with the limited options, just backing up my vote.
EDIT: just seen merchant's post. That.