When you say "invest", what do you mean? If you are thinking about buying and holding until the price goes up, you have a better than 50/50 chance of making some money over the long haul. But it is by no means certain. You should never invest more than you could afford to loose. If you are thinking about buying BTC so you can spend them for products and services, that is a better bet. There are some great deals at bidding websites and others right now.

Trading in currencies is a brutal game, especially in an unregulated/uninsured market. One can make money at it, but then again it's true that one could make money buying lotto tickets.  BTC is a excellent money for buying stuff on the Internet. As an investment it should be considered risky.