I forgot to make a comment on the DR-3. I had one for a while but found it very annoying in the way it handles fills. To explain, if the pattern currently playing is a 4 bar pattern, and you press a fill-in button anywhere within the pattern, the fill doesn't start until the pattern has completed all of its bars, and then the fill-in will play it's entire length which almost always threw the drums out of sync by at least one bar. Maybe there is a way to change this but I couldn't find it.

On the WK2HD-MA, and many other arranger instruments, a fill will occur as soon as the fill button is pressed and will only play as much of the fill as needed as to not throw things off by a bar or more. "I hope that makes sense".