Yamaha DTXpress/DTXplorer/DTXtreme

Hello all,

I am a rookie drummer (to put it modestly) and have been doing some 
research on different sets.  I live in the apartment and quickly 
realized that an electronic set is my only option.  I have been 
checking on ebay and have narrowed my decision down to the old Roland 
TD-5, TD-7, Yamaha DTX 2.0 and the Yamaha DTXPRESS.  I do not want to 
spend too much but I am not knowledgeable enough about the differences 
 between these sets to make an educated decision.  Any advice would be 
appreciated.  Thanks.

Frank