Ive tried several brands.
Im always buying stuff at car shows etc, that apparently are "better" than the rest etc.. but really, i cant see much difference in any of them.
Its the technique/work involved that counts.
If you just wash your car, with a standard "wash n wax" it will look good for approx a week. If you wax n polish the car it will look good for maybe two weeks, but if its machined, buffed, clay bar, etc...it will come up new.
The people who clean the cars in the Mercedes Museum in Germany spend approx 8hours per car & thats two people working continously on the car
Most of us spend 1-2hrs on a saturday morning, while the rain holds off battling to get it done.