Doing a little searching, the price of the Zero Wireless controller for the PlayStation 3 can be found at Amazon for $45 which is $10 less than the official Dual Shock 3. Considering the shortcomings of not being Bluetooth and not being able to turn on the system with the controller as well needing a dongle, the Zero Wireless controller for the PlayStation 3 is a good option.
If you want a secondary controller to go along with a Dual Shock 3, this is a very nice peripheral to consider. Overall, Gaming Nexus found the Zero Wireless controller to be responsive and comfortable. The fact that you'll be able to feel rumble on the PlayStation 3 before the official controller arrives is a plus. There are a few issues Gaming Nexus had with the controller but overall it's a good third party product for the PlayStation 3.