I have seen a lot of topics about people not being able to get all correct metadata from TheMovieDB, after having switched from The TVDB.
Personally I find myself in the same position when it comes to certain tv-series. The .nfo is there with the information and id to the TVDB episode information.
Reading several topics, I understand why the switch is made. However, would it be an option to use the TVDB als backup? In case the TMDB does not return anything? In that case you will get the best in from both worlds, when the first option fail.