I would go for bitcoins, they are the only semi-established crypto-currency at the moment. semi-established meaning, you can actually go buy a burger for it.
My question is: why the Winklevoss twins make a $11 million purchase of one percent of all bitcoins instead of invest less money in a good rig farm that mine bitcoin???
Indeed, they could set up a company that builds its own ASIC miners with that kind of money...
Well they DO have a working product, which a lot of people have been questioning, so they are not a complete scam. On the other hand, ordering now may get you an asic miner in another 10 month...