I switched to the Alesis DM10 almost 2 years ago after playing a Roland TD-6 for 15 years. The biggest adjustment I really ran into was the fact that there is more out-of-the box tweaking necessary to get the DM10 performing to your liking. I definitely don't mean this in a bad way, though, as I've had a lot more room to make a huge difference in the sound and feel of the kit.
I don't regret my purchase at all. As an added bonus, if you still have some of your Roland pads, they integrate perfectly into the DM10 kit.
I don't know much about the DM10 MKII, but if it's like the older DM10, you should be in for a great experience.
--Shawn