Have not used one in my Attak but have driven a SE with the Mega Float. Great ride when you set it for regular trail riding. Very smooth in the stutters.
The bad thing is that when set up for a smooth ride in the stutters it does not handle the larger bumps and bottoms out. Worse than the stock spring in the Attak.
Set the air pressure for the bigger bumps and you get a rougher ride on the stutters.
So it would depend on where and how you drive if it is the right shock combo for you.
I heard / read that Hygear can make the Megafloat work much better.