Yes I have them,
I also have the dragon fly. That reaches up to 20 feet internally. It has a pump and sprays the water (Not a jet like WFP) so remains dry.
They are good pieces of kit when used in the correct circumstances. By that I mean they are designed for maintenance cleans and not for windows that have not been cleaned in ages.
If this is your first time cleaning the pub I would use traditional method the first time then use the easyshine kit or dragon fly.
Im not sure what the prices are now but i paid about£500-600 for dragonfly £74 for the easyshine and about.
Having not seen the windows in question - if they are postage stamp windows either kit will not work.