Beowulf,

The MU-100 is not the same. It's an earlier version of Yamaha's XG synth line. The MU-100 does not sound as good. In fact, I bought a used MU-100 and was disappointed in the sounds and the overall usefullness of the thing. I'd choose the XV-2020 or Ketron SD-2 over it.

The SW1000XG is a PCI board for your computer. My card is a version of it for the Yamaha Motif, and it sounds great. I don't think there is a stand-alone hardware version. I did a quick search of Ebay for an SW1000XG and found a couple in Greece for about $600 each.

The MU-100R is the same as the PCI card, but is a hardware box. If you can find one on Ebay for less than the Ketron or Roland, it may be worth buying. But, they are pretty old now (stopped production around 2002), so be careful.

The Ketron is the only one of the above that is still in production, and has a future.

http://www.yamahasynth.com/products/sw1000xg/index.html

Also, in reference to Mac's mention of the Ketron SD-4 (I think it was), and using its two GM synths independently: I found trying to use the Motif Rack sounds for playing and the PLG-100XG for MIDI playback wasn't as simple as I'd hoped. You can play a MIDI file while you play, but you must stay in "Performance" mode, which means you can't just dial up a nice piano patch to play along. If you change your mind and want to use an organ patch during a song, you can't do that from the keyboard. You have to send the instrument patch via MIDI from a sequencer. I tried it live, but it proved to cumbersome (and the unit is too heavy!).

So now, (not to sound too much like I'm plugging a particular product!) I have a Ketron SD-2 tucked in the back of my rack, connected via USB, audio thru the Ultralite, and I'm very happy.

I tell you all this detail, not to push a product, but too share my experience with what's out there.

Dave Burns
Lowell, MA