Yamaha DTXpress/DTXplorer/DTXtreme

As I always blab about, the DTXpress was released her in Japan and 
seems cool. In the catelogue, there are also two amps that are custom 
made for the DTXpress. Has anyone heard of these? (I'll post the 
model numbers when I get home) Have they been available in the past? 
These days, I'm looking into amps and there are many choices. I just 
read the post about the Behringer amps. They sound nice too. I'm sure 
it's been discussed to death, but what do you look for in an amp for 
e drums? Keyboard amps? These Yamaha's will cost a lot for me here in 
Japan. Everything does.

Jon in Japan