hersey the xp 50 is based on the 1080 sound engine/xp60-80 are based on the 2080 you can edit all the perameters its just not as easy as the 60/80
still, if someone only has $500 nothing comes close to the 50,you can spend $400 more for another four exp cards and have about
1600 sounds on hand for a total of $900,and the sounds are current,just look at any true production house no triton or trinity but a 1080,2080,3080 or 5080,nothing fucks with the roland sound engine