Im primarily a landscape shooter with a 5D2 and 7D. There is no doubt the 5D2 makes better images than my 7D and it was the same back when I compared my 40D and 5Dc. But, the differences arent as stark as you might think - a little sharper here, a little less noisy there etc - but no wins by knockout, especially at ISO 100.
There are 3 areas where FF really has an advantage:
-Using the wide primes in their native FOV - TS-e 17, TS-e 24, 24 1.4, Zeiss 21 etc. These lenses kick the snot out of anything a crop camera has to offer.
-Long exposures are significantly less noisy with my 5D2.
-If I need to stop motion in low light, my 5D2 does a much better job at keeping the noise down. For example, if Im doing a sunrise shoot, its still early and I dont want a glass surface on the lake - actually want to see the waves - I need to crank up up my ISO to 1200+. The 5D2 images look better - although I still end up exposure blending the waives in so my sky and foreground are still ISO 100.
However, crop cameras have their own benefits for a landscape shooter:
-You get more DOF at the same aperture which means shorter shutter speeds for more handholdability (nice for hiking w/o a tripod)/lower ISO to get the same DOF.
-IMO, the 10-22 is superior to the 17-40.



