getting one so iv being looking at them , others might have experience of using them .
Weight depends on materials , some are all titanium or part titanium so may be lighter than two.
If you want a low profile head u would need at least four jets to get the spray coverage especially if u go over 12"
A low profile head is probably needed to facilitate a swivel action on the newer wands if u want that .
Multiple specific angled jets probably have some pressure/flow advantages over two jet .