They did worse than expected in nearly every race. That's not to say the Libertarians have not had a great year, because they certainly have, but Libertarians did significantly worse than polls projected because of last minute fear tactics employed by the two major parties.
Overall, not too shabby this year as a whole. Many LP candidates got into nationally televised debates, a big win for any third party. Lucas Overby (FL-13) got 25% of the vote...a record for the LP. No candidate (that I know of) got below 2% and many got above 5%. Party registration for the LP is also way up. They are doing pretty good and I think we can expect great things in the future.