Oh, I had the same problem when I tried to create an account. It happens because sometimes it says the user name isn't taken but it in fact is. I kept trying to create an account with this name (The Random One) and it said the name wasn't taken, but it kept giving me a failure. The one time it told me the name was taken out of the blue; I tried a different name and succeeded at creating an account.
It looks like it sometimes doesn't check properly with the login server, and then it fails to create an account because the name is already taken. Fortunately, I have a private nonsense name I use for those sitations, flaetsbnort. I recommend you do the same. If you do not have a nonsense name, I recommend snarfblat. It may already be taken, though.
As for whether it's worth or not... I hate it with a passion, but I'll say it's worth it. Just for TF2 if nothing else.