The limited ground texture resolution of FS9 is a big problem for photoreal scenery. 5m/pixel is blurry.
Nevertheless, when the author adds a good autogen on top of those photoreal sceneries, the result can be really pleasing to the eye. Only thing is: photoreal sceneries have almost never any autogen at all, so you get only this big flat and blurry area.
It still looks really cool for high mountains and deserts, however.
When it comes to the colors, don't forget that those pictures are taken from an airplane or sattellite. The colors will be impacted by the weather at that time. Normally, the photoscenery creators try to limit this impact by modifying the pictures prior to use them in sceneries, to ensure that all the concerned zones blend correctly together.
The problem is exactely the same in FSX. Although FSX allows a much greater ground texture resolution (up to 7cm/pixel), if you have no autogen or if the original pictures were not modified/arranged by the creators, it will not look so good, at least not a low altitude...