Playing them both is just a dream. I never really thought about it but I would say I can't really taste a difference. I really like them both for all the right reasons.
I do remember the first time I played a piezo pet, I took it into the acoustic room to get an acoustic amp. One of the salesmen came in and shouted, "Who's shredding on the Martin?!"
They became "Had to have " options on guitars ever sense. They add just the right amount of mass to the trem for me.