Canon 7D(EF-S 15-85 IS USM) - Nikon D300s(AF-S 16-85mm G ED VR)
The Canon has more noise in low ISO rates but in higher ISO rates is better than the d300s. (incorrect the high ISO's are equivalent (if not better) in the d300s in many situations but the results Ive had are different than what you have)
The Canon USM lens are faster than the Nikon AF-S series. (also wrong, it is more dependent on weather you are using a newer or older lens in either system, until the mid 2000's canon lenses were faster but now they both are identical, it is more dependent on what lenses you test.
The D300s colors are closer to the reality, the Canon is a little bit reddish.
(that is somewhat true indoors but outside not so much)
Which AF system is better? I mean speed and accuracy, low light performance?
(both are about equivalent but canons is a little more accurate and fast using crappy lenses than nikon. Nikon however is more accurate in low light)
The Canon AF sensor sensitivity in the center are from F2.8 and the others F5.6. In the nikon system are all from F2.8? (dunno)
OK, the Nikon has more AF points.. and the Nikon can make 3D tracking. Canon?
As I heard if you use auto AF you can also use the manual focus ring. Is it true? In the Nikon system is it possible to manualy corrigate the AF in auto mode or it kills the AF motor? (you can absolutely override Af in almost all of the newer nikkor lenses with MF just make sure your lens is set at af/m, it won't damage the lens in the slightest)
The Nikon TTL produces more neutral exposures w/ flash?
(yesish all strobes fire at 5560 k so that is more dependent on your camera settings)
BTW you took these in Mel's didn't you?