When I saw him in Europe fairly recently he played one song on the hollow body and one on the green strat style Jem.
Then it was roughly 50:50 between Pias (a black one and a green one) and the usual Evo Jems..
Might've been a UV in the mix for one or two songs as well I wasn't keeping count.
For me, play the one you like the look of and feel/sound of.
I played a Jem for a decade before really getting into any Vai music (other than with Zappa). I'm still more of a Jem fan than I am a Vai fan. So there's lots of reasons to buy a signature model.
Then it was roughly 50:50 between Pias (a black one and a green one) and the usual Evo Jems..
Might've been a UV in the mix for one or two songs as well I wasn't keeping count.
For me, play the one you like the look of and feel/sound of.
I played a Jem for a decade before really getting into any Vai music (other than with Zappa). I'm still more of a Jem fan than I am a Vai fan. So there's lots of reasons to buy a signature model.