I am new also (one week in). What kind of biggest loser contest did you join? There have been some local ones, including some that you have to pay for (through personal trainers). I never took the leap. I admire you for signing up.
So far the logging is great! I have seen some complaints on the threads about the ads, or the accuracy of the lifestyle calories. However I think that I can make it work. (I started adding sleep as an activity based on what some in the threads said).
As others have said, knowing that you are logging certainly helps with the choices!