At this point, I would have to say Ripple (xrp). Seems to be the one with any kind of legitimacy.
Nothing says legitimacy like a giant premine arbitrarily distributed by a for-profit company.
Boo this man! BOOOOO!
I'm going by performance to date. Ties with banks. Ever increasing value. How many other coins have that going for them?
I bought Ripple just to play with. My xrp is looking pretty healthy now unlike all of the other coins I own. Surprised me too.