Paypal Jumps Into Bitcoin With Both Feet
You'll get lots of different opinions, but there are plenty of weaknesses
1. Mining is centralized, and there's no incentive to decentralization
2. Mining is quite wasteful
3. The block size is too small for high transaction volume. Solutions require more nodes, but as the blockchain grows running a node becomes more expensive.
4. The prices is too volatile
5. Bitcoins aren't fairly distributed.
My main gripe is that the price of coins is dictated by the cost of mining them, and is not related to the cost of keeping the network secure. (https://bitcointalk.org/index.php?topic=600436.0)
Despite all this, the increase in adoption in the last twelve months has been phenomenal. Many large retaillers (Expedia, Dell, Newgg) have started accepting bitcoin. Hundreds of ATMs have been rolled out. Numerous financial products featuring Bitcoin have been confirmed. So on the one hand, Bitcoin has some serious problems, but on the other hand, there are a lot of people with a lot of money interested in keeping it going.
Correcting Misperceptions About Evolution
Good, but I think if you really understand evolution, there's a chance you're going to want a bacteriophage instead of an antibiotic anyway.