DON'T pay $3500 for a used MC-1! They can be had much cheaper than that. Even from a dealer, I wouldn't pay more than about $2500. Keep in mind, however, that Lexicon offers generous upgrade programs on their pre/pros, but each unit can only be traded in once in it's lifetime - it would be worth some extra $$$ to buy one that could be traded in in the future. My guess is that your dealer would be selling you one he rec'd on trade, so then it's really way too much
I owned / loved the MC-1 for 2 years before trading mine in on the new MC-12. It's awesome for movies (which I watch a lot of) and I found it to be excellent for music. I haven't compared it to a lot of other units, but it was extremely well reviewed even for music listening. I don't know if it's better or worse that the SP-1, but I think that at $2500 (esp. if it remains eligible to trade in later), it's a great piece and I would highly recommend it. -Kirk