I just bought a CDV300F from Taobao and I can tell you what the differences are;
Like the CDV300x, the F model does have Super HD (SHD30 2304 x 1296 @30fps)
The F model does not have GPS
The F model has dual Micro SD card slots. If you set it to NOT overwrite files when the MicroSD is full, it will automatically switch over and start using the second card.