Unless your fitting into vans for staff, you can really save your hard earnt cash and make one yourself, with a hose guide as well.
Your saving energy and a slight bit of time by using one and thats even standing next to it with a rag, cleaning the hose from grit as it winds in.
Many a window cleaner has done a diy version and they work very well. I had mine for a couple of years before i sold it all on (could be wrong but its still in use as far as im aware).
I ran mine of a seperate 12v 110ah leisure battery (all be it, trickled charged from a solar panal on top of the van and periodically (through winter months) with a smart charger over night on the drive.