Hey Thumper. I know you were waiting for the TD-20 fix. As far as the TD-20 and Alesis DM-10 comparison, he is what I think.
1) Cost- DM-10 better bang for the buck. Roland Module > $2K DM-10 will probably be $600- $700 (according to 109)
2) User friendly- DM-10 easier to use for the Zendrum
3) Using crossfades and stacking sounds- DM-10 done without any problem- big problem with Roland
4) DM- 10 also has the capacity to function as a midi interface with computer. Not with Roland.
5) Quality of sounds- ( I also have the TD-20 with expansion board) I think the sounds are better with the Roland. Alesis sounds muddy and muffled. Cymbals much brighter with Roland( more $)
6) If you are a sound engineer and understand all the capabilities of the Roland- (You are my idol) and you can really tweak it out with some limitations.
7) With that being said, I may have grown accustomed to hearing the sounds of my module and that is my preference. This stuff is really personal preference.
I watched 109 with his Zendrum and that Alesis module and he kicked it and I was in AWE. He sounded wonderful and played outstanding.
9) It was great to see him so satisfied using that module and I think he is really happy with the way he set it up.
10) The Alesis module is a nice fit for someone who wants to get a good combo Zendrum and Module for about $2000.00
11) I hope this helps.