the PA4X is a nice unit for sure if it was me I would get a TYROS 5 befoe the Korg

i find the T 5 much easy to run both are great i just love the t 5 guitar screen , keybed, midi file player support ie yamahamusicsoft.com if you play any clasic music the emsamble section really great larger buttons layout larger to the eyes

lot of great things on both i prefer yamaha T5 you have T 4 That is a great unit as well I still have mine and really like it but soon will upgrade it to another T5 to leave at a gig and i travel with the other one .