Regarding the high speed transfer from PC to MD, the new NetMD models from Sharp and Sony promise high speed transfer capability using Sony's OpenMG software and your PC's USB. I have a Sony MZ-N1 and it's fabulous, but the OpenMG software is not quite so fabulous. Actually, almost every review I've read about OpenMG has completed trashed it.
One of the limitations is that you have to use OpenMG to convert your files or CD to ATRAC3 (highest quality allowed is 132kbps) before sending to your MD. Transfer speed depends on the recording mode you choose. Once the files are converted, they transfer quickly at LP2 and still sounds good, in my opinion. But if you factor in having to convert all your files and CDs to ATRAC3 with OpenMG first, then it's not really that fast.
If you want to transfer in SP (uncompressed) mode it is kind of pointless with OpenMG since you are limited to 132kbps and it doesn't really transfer much faster than a realtime recording. You're better off just making a direct recording from your source and the MD's line-in. I've never tried LP4 but it's supposed to be ~30X realtime but has poor sound quality.
I think my MD is fabulous. It sounds great and has exceed my expectations. Hopefully the software will be improved in the future and allow faster, higher quality transfers from PC. Until then, if you want to make *a lot* of high quality recordings quickly, you would be better served by having a dedicated MD deck/CD combo that has high speed dubbing rather than fool around with the OpenMG software. Of course that's just my opinion.
If you're at all intersted in a NetMD minidisc recorder, take a look at this review:
http://www.minidisc.org/brian_youn/mzn1/page1.html
Cheers!