I've owned both. Had a ZBoard, have a Boosted Board.
The ZBoard is utter trash compared to the Boosted Board. Build quality, ease of operation, sound of operation, ride quality are all far superior on the Boosted Board.
As someone with a fair amount of experience on an electric board (ZBoard type), I like that Boosted puts the battery packs and electronics at either end of the board. Other boards have the battery pack in the middle and it gets in the way of clearing obstacles.
Also, hand controller works nicely for me so I see no obvious advantage to having my weight distribution impact the board's motion.
The ZBoard is utter trash compared to the Boosted Board. Build quality, ease of operation, sound of operation, ride quality are all far superior on the Boosted Board.