Yamaha DTXpress/DTXplorer/DTXtreme

I was just wondering if anyone on here has done a side by side 
comparison of these two modules? Specifically in terms of sound 
quality. I've heard the ddrum4 demos and love them. But the features 
of the DTXtreme are great with the sampling and all. And there 
doesn't seem to be any sound demos of the DTXtreme IIs on the web 
either. Well I hope to demo the DTXtreme in person at samash this 
weekend. I won't be able to demo a ddrum4 in person though. Any 
opinions out there?

Thanks,
Ken