I've migrated to LW because threaded discussions are SO VERY MUCH BETTER! Locating old posts is easier; commenting is quicker; karma is fun (and a rationality test - not the getting it, but the not caring too much about it).

EDIT: The ability to edit my comments is also a huge win. I always write something wrong the first time, even when taking this rule into account.

Also, if I catch up on my reading and make 3 comments, on OB I have to wait an hour before I can make a 4th comment.