Yeah, I've got the 2G card. But 2 things:
1.) If you use the card for other stuff also, the MPC doesn't like space is foolder names, and sometimes it doesn't like them in file names. DON'T USE SPACES. In fact, try using "8.3" dos format file names too (that's really what FAT16 format support directly anyway, and you'll save yourself problems), and you won't have problems.
2.) WAIT. The Microdrive isn't as instantaneous as Flash cards, and when you use a large size like 2GB, it takes a few seconds for the MPC to read in the directory structure. It's not a painful wait, but the MPC doesn't give you progress bars or anything to tell you it's working. Just be patient, and you'll get used to it (it's faster than a zip drive, but slower than a regular hard drive).