what's the biggest difference between ipad and apad?

Nowadays,many Wholesale China Electronics online store sale cheap ipad clones so called --apad/iped/aped. The device is quite different in terms of specs to Apple’s iPad, but the design is exactly the same style as you’d expect with the iPad. The aPad or ePad has the Google Android Operating system which is also used in a large number of cell phones and PDAs . The beauty of this is that it works seamlessly with Google Applications like Gmail, Google calendars and Google Maps. Emails and calendar information is synchronized when the aPad device is connected to the Internet via Wifi. iPads on the other hand runs on iOS 3.2.2 which also runs on the iPod touch and earlier versions of the iPhone. It works seamlessly with other Apple products and services.
The biggest difference between the two, is that the iPed runs Android 1.5 OS or even the newest 1.6 os, rather than Apple’s iPhone OS. And Applications for the aPad are available on the Android Marketplace. With thousand of free Android applications available, one will still have fun downloading and using these programs.
The awareness is growing by the day and a good number of individuals are accepting the aPad as a nice alternative to the iPads. Apad Android are more and more popular among high school students just for it's much cheap price. And many of students are light users,they needn't the more advanced applications. All in all,compare with apple ipad ,apad android have a more general Operating System,but many people still prefer apad for it's cheaper price.

aside from google android version 2.2, what are the other operating system of APAD Android version 2.2?