I received my Magic Rinse system and have just used it for the first time. I'll post a mini-review once the car has dried and the results can be judged.
Car is dry now and as advertised, there are no spots. The unit weighs about 6lbs, but is easy to hold via the integrated handle. Hooking up is easy: water hose in, sprayer hose (included) out. Once the hoses are attached and water turned on (says water pressure should be between 20-100psi. Mine tested at 65psi) all that is needed is pressing the vent button to purge air, then turn on the spray. The sprayer nozzle is the only thing I didn't care for. It sprays a fine stream instead of a mist like my previous system. It works fine, and most likely is more efficient than the mist, but it took some getting used to to adapt. Instructions say 1-2 mins should be all it takes to cover a car or truck. It took me 5. Mostly because I even sprayed the wheel wells and every gap.
So my verdict is that it's a good buy. It only costs $129, and the cartridges are good for 15-20 rinses (I'll likely get 10 because I go overkill). Spot free with no towel drying. Good deal!