It's photoscenery SO it's FPS friendly.
Photosceneries often have very sparse autogen (most of the times, no autogen at all) and very sparse scenery objects. As a consequence, there's nothing to hammer your CPU, other than the usual texture loading.
Knowing Frank's stuff, you should be good to go

thanks.
this got me over my fear of downloading even more photoreal scenery since i am a fan of photo-real.

Depends on what kind of flights you like.
Photosceneries without any scenery and autogen are absolutely terrible and ulgy when it comes to low-and-slow flying, bush flights etc...
Photosceneries WITH autogen and scenery objects can be extremely cool though. The problem is:
- you only get one season
- you often get only DAY textures, which look terrible during nights/evenings/mornings
- you almost never get any autogen/scenery.

That's why, for now, nothing beats the generic textures with good landclasses.

Like Boikat said, I only enjoy photosceneries in those place that never change all year long (tropical, deserts etc...) and only in places where I fly at a certain altitude. I love the Death Valley scenery for example, and I also love the Kauai island, but I never fly them at low altitude. I only fly those places at medium-high altitude, often with military jets