Never used one on grass.
Doing one right now, ex railway with a 6" diameter brush on the front.
Sucks off a hard surface really well, did a great job on the 2' square section of the floor it could get at.
This has a GXV 160 in it.
It is also all plastic which makes it a lot lighter than the Parker I inherited with the business that has a steel frame.
The plastic frame also feels sort of clumsey.
But it does suck really well.