There is also a less-expensive unit MZ-M10 which is a rebranded MZ-RH910. Since the list price of this unit is $110 cheaper ($440 versus $330), you might wonder what you are giving up. Very little. It has a 5 line LCD display instead of the 6 line "Organic Electroluminescence" display, but is .2oz lighter and rated for 1h more battery life.
These units work identically to their brethren on a Windows box. For Apple they can upload recordings made on a Hi-MD disc in PCM format only, not any compressed format. Furthermore, only recordings made through the mic/line input, not the optical input, will upload. As a final limitation, you cannot download to the units on the Apple.
Here is a review of the unit that has some further comments.
The Mac software will not work on the older model MD, even though they are identical in hardware. Sony has stuck some new encryption code in the files themselves to prevent this from happening, a brain-dead move. On my last project it would have been useful to upload to a Powerbook from my MZ-RH10, but no go!