> I've never played an SDS9 before, and am just wondering...
>
> Is it basically like 3 channels of SDS7 and 3 channels of SDS8/800
> (without the run generator?)?
reduced to a simple formula: you may say so (BTW: SDS800 was later than SDS9). The experience from SDS7/8 combined in a consumer priced desktop device extended by some new features like 2nd-skin, Midi-Delay and the midi implementation itself!
>
> Or is it fundamentally different?
I'd say the most fundamental difference where the pads
>
> The MIDI capacity makes it tempting. MTM's seem to go for more than
> SDS9's...
SDS9 brains appear far more often on Ebay because they have been produced in a much higher quantity. Since 2010 there have been only 4 MTMs on Ebay (US, UK, EU) with an average price of 180 Euro. Compared to that SDS9 brains have been sold 25 times (sometimes with pads, sometimes not), the average price for brain-only-auctions was 130 Euro. So you are right :-)
>
>
> all my best,
> - Scott
>