I am...I won't be upgrading he XS8 to the XF8 but I am sure the T4 will be a worthy upgrade. (as long as it doesn't have two keyboards and pedals.....)
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Yamaha Tyros 4
Yamaha Motif XS8
Roland RD700
Casio PX-330
Martin DC Aura
Breedlove ATlas Solo
Bose MOD II PA