I haven't heard anything about the analogue to ADAT adapter?????
Anyway, the Digi 001 is outdated. I don't know how much longer Digidesign will continue to allow it to work with Pro-tools, but it does have more inputs that the M-box.
The M-box has 2 I/O and runs on Pro tools LE which can handle up to 32 tracks. The newest version of Pro-tools LE (6.4) comes with the M-box as well as a factory bundle.
It basically depends on how many simultaneous tracks you plan on recording as well as how long you'll be wanting updates.