I used to have a R-8 mK II. It was a very good drum machine. I should never have sold it. I recently auditioned
a Boss DR 670, and was appalled at the interface (hold 'shift,' press this button, continue holding shift, press that button, etc). I am not sure about the differences between the R-8 and the mK II, but if the price is reasonable, I'd go for it without hesitating. It doesn't have all of the preprogrammed patterns that the Boss has, but the interface is better, it likely has more than a stereo out, and the sounds are perfectly acceptable (and can be modified). The other one I'd grab without hesitation would be an R-70.
Hope this helps.
