Ah, here's a few:
Pro's:
1. Small (great for stealthing)
2. Cheap media (and small too, pretty reliable as well)
3. Media does not get worn or chewed up
4. Generally good sound (especially the sharp units)
5. Great battery life
Con's:
1. Some people frown on MD tapes
2. Artifacts can find their way on a recording (sometimes)
3. Some units are fragile
4. Not worth fixing once a unit breaks
5. Lack of optical outs on recorders (grrr)
I'm sure i'll think of more as this thread progress.
I own the following portables: Sony E75 (blue and red models), Sharp DR7, Sony MZR50, Sony MZE33
I own the following deck: Sony MXD D5C