Yamaha DTXpress/DTXplorer/DTXtreme

Can someone please share with me any knowledge they have on the 
differences between the Roland TD-5 sound module and the module for 
the DTXpress?  I have been bidding for the DTXpress unsucessfully on 
ebay for a month and am considering opening up the search to include 
the Roland TD-5 as well.  I am trying to compare the amount of sounds, 
user editable kits, etc.  I know that the DTXpress has songs that you 
can play along with and mute the drum part but I don't know about the 
Roland.  Also, I don't know if Roland has anything similiar to the 
Groove Check function.  Thanks for your help!