So, I'm liking the look of bitcoins.  Secure, anonymous, decentralized.  I think they'd work well as a currency for use in tor or i2p, "behind the veil" as it were.

But bitcoin isn't the only player out there.  There's at least a half dozen other alternative currencies vying for adoption.  Wikipedia just has crap, it's made of marketing and herp for a topic this narrow.

So tell me about them, if you'd be so kind.  What makes them good?  What makes bitcoin better?  Which are the players and which are the underdogs?