Overall, I am personally just not impressed by Hogwood. His handling of the phrases is rough, and the music just doesn't seem polished. Occasionally the balance is questionable (for example, several clarinet passages in the first movement of the 39th stick out), and at other points I get the impression that he put little planning into the organization of strong and weak bars. Perhaps it is mostly personal preference, but other conductors really do sound better.
I think that this recording has its place, as there are few boxed sets of all of Mozart's symphonies available, and certainly there was some groundbreaking period instrument work here. I would, however, strongly recommend that anyone considering purchasing this set actually obtain a copy first from a library to decide if this is really what they want.