Going to be doing a lot of shooting in a small house, and a medium size school classroom. I've heard good things about both of these mic's. Which would you folks recommend for this?
The 4073a has the best sound, but for a really tight interior the me64 has the best pattern... so under these conditions only I'd have to give the me64 the nod.
(If these rooms are both small AND echoey then you probably won't be happy with either... I'd expect a cardioid or lav to be the best choice then... and get the mic as close as possible to the mouth or just outside of frame.)
I haven't used the AT but I have the K6-ME series. Try to get the ME64 within arm's reach of the talent if you can, and all will be fine. Like Matt said, if it's a really small room it will be echoey. Hope for lots of curtains, carpets and bookshelves.
For the more open classrooms, you might give a listen to the tighter patterned mic (4073a). It might sound better. Yet, some classrooms have mighty echos.