they've pretty much said they'll be releasing firmware to fix the 2gb size limit - either before or after its released. they've also said that it doesn't matter what card you throw in there, it should work just fine.
the microtracker isn't pdaudio, ones from m-audio, the other is from core-sounds. *shrug* take it for what it is i guess. but something tells me the quality control at an international company like m-auio is better than a privately run core-sounds.