I'd be very interested in learning the differences in quality between ZeroSurge and these guys. I've been relying upon and recommending zerosurge for years in the AV space.... my 1500VA unit only cost around $120, and even though it only has two outlets, it otherwise looks very similar and has been very reliable.I believe ZeroSurge, Electronic Systems Protection (ESP) and SurgeX are all related companies.Do one on ZeroSurge
I suspect the multiple brands / companies is either because of legal / tax business structure, or different market focal points (Pro Audio, IT, etc.).
ZeroSurge products should be remarkably similar in design and manufacturing quality (I think they are manufactured in the same facility).