Dunno about the FP-6, but you said you had a Remington. If that's an 870, you've got the best. There's DIFFERENT shotguns, many of great merit, but none better.It's fun and educational to try different shotguns out, but any shotgun battery w/o an 870 is quite arguably incomplete.
You can do what you like, of course. But, I would think your proficiency and effectiveness would improve more by sticking to one model shotgun,and if you want another one, get something completely different, like an auto or double, instead.