The Super Fuel Max looks easier to install and their add sounds more impressive:
The Super FuelMAX operate on the principle of magnetic frequency resonance. Using super-conductors made of a formula of Neodymium blend (NdFeB37), which is covered by worldwide patents, the Super FuelMAX creates a specific resonance that breaks apart hydrocarbon chains and makes combustion more efficient. The result is lower pollutants and piston friction reduction, thereby increasing gas mileage up to 27%
FuelMAX
it's only $49.58 :p