I'm skeptical how well it truly works on uneven surfaces, and it's certainly WAY overpriced for what it is.. but if you're not handy with tools -- or don't have them available, it seems like a fairly solid piece of kit.
On the other hand, it looks like it could be built with a handful of parts for probably less than 1/4 of what they're charging there.
Either way, personally I'm much more a fan of dolly shots than steadicam shots.
Looks alright, but seems pretty simple in its design for the asking price. Maybe you should look at some DIY dollys before making that type of investment