Before you purchase the MM6 with the intent of MIDI usage I strongly suggest you go ask questions at the Motifator site about what you're wanting to do in terms of Midi with the MM6. There have been TONS upon TONS of complaints about the midi limitations on the MM6. You may want to speak with the other MM6 owners there before you purchase the unit. It may or may not function for what you need.

I can tell you that IMO the Juno-G sounds much better in person and much better through a decent set of speakers too. When I first played a Juno-G it sounded like crap because it was running through a crappy mono speaker system. My second run with it was on better speakers.., my third run was with good headphones and it was like silk

Don't be turned off by SRX boards being an extra purchase. The Juno-G accepting SRX cards by no means translates to the onboard preset patches being poor! The purpose of the SRX boards allows Roland users to tailer their sound sets in many ways to suit their needs. Roland gives you great preset patches.., but offers the SRX library to customize your keyboard. If you're like me and into orchestral and film score music.., well Roland gives you good onboard patches for that, but offers SRX boards that cater to my lust for orchestral and film score composition Keep in mind that the Juno-G's sound set is to appeal to a WIDE range of music styles. The patch set is designed to appeal to a large group of people. One great thing about the SRX libray is that they really are pretty reasonably priced and when you add one of those puppies it feels like you just got a new keyboard (but for much less).

The MO's do sound really good too. I used to own the MO8. It's as close to the Motif ES as you're going to get. The MM6 will get you no where near the sound quality you get on the ES or even the MO line (especially in the synth and sequencing area). Some people find the OS a bit difficult.., but that varies from one person to the next.