"I haven't had any luck on selling the DR-3. I posted it several places and haven't even got an email of interest just to make an offer. I may keep the WK3500. Not sure on that yet. I'll have to see how desirable the 3500 is in the used market after the 3700 is released."

Ahhh given the timeline john gave for the new ones to come out, lots of time to save cash. If you cant sale the DR-3...just use it, even if you have another drum machine there has to be things each one can do the other cant. Heck combine the two machines and see if you can come up with some stuff...couple of different loops off different machines combined can have cool results.