D80 is a mid-range machine and 600D is an entry-level machine. Nikon may focus better in low light. Nikon's is suitable for shooting scenery, and Canon's is suitable for shooting people.

But D80 has been discontinued, right? The D90 has been discontinued. Moreover, D80' s photoreceptor is CCD, which has poor sensitivity and is not suitable for use in places where indoor light is not very bright. 600D photosensitive device is CMOS, which has better high sensitivity. It is recommended to enter 600D d.