[zenith (Tim)]

I am about to purchase my first digital SLR (I owned a 35mm film SLR in high school and currently have a Canon powershot and Ixus). I will use the camera for terrestrial and beginner astro-photography (starting with nightscapes and the moon using an ED80).
I have almost decided on a Canon 6D and Sigma 24-105 F4 DG OS HSM. However from a cursory glance on DXOMark.com, the Nikon D750 with AF-S NIKKOR 24-120mm f/4G ED VR Zoom Lens appears to have superior dynamic range, sharpness, larger effective ISO, and more features (veri-angle view finder, pop-up flash, faster continual shooting speed etc).
However Canon appear to be more popular in astro-photography circles. Is that because of useability? Or is there more free software/laptop control options?
I'd really appreciate your thoughts and experiences.
Thanks.