The Qualcomm Snapdragon S3 MSM8260 is an entry level SoC for smartphones and tablets (mostly Android based). It contains two Scorpion cores (enhanced ARM Cortex-A8) clocked at up to 1.5 GHz, a Adreno 220 graphics card and radio elements. Compared to the similar MSM8660, the 8260 does not include support for CDMA2000.
The similar named MSM8260A already contains the faster Krait cores and the slightly faster Adreno 225 graphics card.
The Rockchip RK3066 is a cheap ARM based SoC for Tablets and Smartphones. It integrates two ARM Cortex-A9 (ARMv7) CPU cores with NEON extensions, a ARM Mali-400MP4 (quad-core clocked at 250 MHz) graphics card and a video de- and encoder as main components. The integrated memory controller supports a maximum of 2 GB DDR1, DDR2 or DDR3 memory.
The CPU cores can be clocked up to 1.6 GHz depending on the cooling solution of the tablet / smartphone.
Additional Features according to Wikipedia
VPU (Video Processing Unit) Multi-Media Processor supporting 1080p image and video decoding
HDMI 1.4 Interface
2-channels TFT LCD Interface with 5 layers and 3D Display (1920×1080 Maximum Display Size)