But given that 1 BTC is ~ 20 USD at the moment and that over much of the last year it has been varied between roughly 6 USD and 14 USD, you would have roughly doubled your money.
The question is really what the future holds. Will adoption grow dramatically (in which case BTC will give an amazing return) or is it a white elephant.
Extremely high risk investment: potential high returns, high risk of total loss. Mind you, some high risks investments are needed in a well balanced portfolio.