Any company can put a powerful motor in, but the engineering around it is what really makes a superior product.  Even though everything is plastic, which is to be expected, the connections are solid and well designed.  They are clearly marked, work well, and snap into place without a struggle.  The only function of questionable utility is the appliance wand, but then I realized that I didn't have any ideas to improve it, so I'll just accept it for what it is, semi-useful.  The best feature for me is to be able to lift the canister and walk with the power unit and hose to get those nasty spider webs on the ceiling and fans.

Pros: Well designed and powerful, easy to empty and no bags required.
Cons: The wand is the weakest feature, but perhaps it has to do with my techniqe rather than design.