One of the latest tests of the device I've seen is a set of website load times compared to the ARM11-powered iPhone 3G, T-Mobile G1, and myTouch 3G. How long a webpage takes to fully load may not be the best way to measure a processor's performance, but it's one of my favorite methods and the results are easy to understand.
As you'll see in the table below, Rockchip's 720p-decoding RK2808 isn't as powerful as the ARM Cortex A8 found in the iPhone 3GS, Archos 5, and other mobile devices, but it does enable faster page load times than ARM11 phones.
To give you an idea of how much faster the Cortex A8 is, the iPhone 3GS loaded Amazon.com in just 8 seconds here in Hawaii (the tests shown in the table were conducted in China).