I'm currently using a big guy but I'm looking for another one because I recently put together another rig. No complaints on the big guy but I think it works better on an 8gpm machine and both of mine are around 5gpm. It works great at a slower pace but leaves stripes when you move fast.
For those that do not know, Whisper Wash can add the tires and solid handle like on the Big Guy to the 24" Ground Force instead of the 4 caster wheels, they call that option the "Little Big Guy". I forgot how much it was but I really like that idea, those surface cleaners are a lot lighter than my 24" Steel Eagle.