Both the Remington and the Nova are excellent guns. I own an 870 and a Nova. It really is going to depend on what you feel more comfortable with. Take a look at some of the specs of the gun:

Remington = 1 choke tube included; Nova = 3 choke tubes included
Remington = no magazine cut off; Nova = has a built in magazine cut off
Recoil - The Nova allows you to insert a recoil reducer (bracket+mercury insert) for about $60-70

Again, the most important thing you can go with is what feels the best since each gun is reliable.