Mellotronists

Whether rack-mount or keyboard model, synths sound different when 
different keyboard controllers are used.  Each manufacturer has its 
own ideas about how velocity sensitivity curves should be applied, 
keyboard scaling of filters and amplitude, and that may account for 
the perceived difference between the Emu products discussed - I have 
no idea if the same samples sets are used or not in those particular 
boxes, but I've noticed how much different other synths can sound 
when used with a different keyboard.