I'm a former owner of the XP-60 and I can tell you that there is NO internal difference between the 2 boards. One has 61 keys and 1 has 76 keys.. That is the ONLY difference between them. I bought the XP-60 because I didn't have the need for 76 keys.. It all depends on what you want out of it. If you want more keys for playing then the XP-80 is your choice, and if you want a feather weight 61 key version that's shorter, lighter and easier to haul around then go for the XP-60... Hope this helped...
Squeak
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GEAR: Yamaha MOXF-6, Casio MZX-500, Roland Juno-Di, M-Audio Venom, Roland RS-70, Yamaha PSR S700, M-Audio Axiom Pro-61 (Midi Controller). SOFTWARE: Mixcraft-7, PowerTracks Pro Audio 2013, Beat Thang Virtual, Dimension Le.