Unless you like spending about 3-4 times (maybe more) as much time cleaning, you are selling the wrong rifle. I personally don't own either but I have 7 other muzzleloaders and friends that have both the Omega and Remington, and the Omega is probably the easiest/fastest to clean muzzleloader made and the 700ml is probably the hardest/slowest to clean IMO. Some of the Remingtons shoot good (some don't), but EVERY Omega my friends have shoot very well with saboted bullets and even three pellet loads if you want to go there.
You will have to make the decision, but if it were me, the Remington would be gone in a flash.
Try this, it may help you make your decision. Take each rifle in there clean state and time yourself taking them apart, breech plugs out. Take the bolt out of the Remington and take apart, see what a pain it will be cleaning out the blowback out of the action, off your scope and exterior of the rifle. Now think about the Omega, no blowback on the scope, everything is just so much easier to clean. Just something to think about.