Will FileVault 2 wear out my SSD faster? I'm considering using FileVault 2 when I upgrade to Lion. Though my understanding of it is weak, it seems as though it shouldn't really increase the number of reads or writes per disk operation compared to a non-encrypted drive.

I don't even know if there's any kind of encryption that would increase reads/writes dramatically, since all decryption presumably happens in memory. But it seemed like something I ought to ask about.

Is there anything I'm not aware of here that I should be?
Encryption happens on-the-fly.  If the data was written to the hard drive, then passed through an encryption algorithm that then deleted the written data and re-wrote it, encrypted, that would be hella inefficient, and would largely defeat the purpose.  I think the answer to your question is no, but of course remember that if you're going from a data set that's not yet encrypted, then all of that data needs to be processed, so that initial process of reading, encrypting and re-writing data will have an effect.