I don't shoot 3 gun and I haven't tried the FN shotgun.
I put just over 8,000 rounds through a black synthetic VM field gun with a 28" barrel over 54 weeks. During this time, I shot some of my best scores at sporting and recorded my first 25, 50, and 74 straight in skeet(missed my last shot on low 8). The gun had very light recoil and would reliably cycle anything from 3/4 oz at 1200 fps and up. One thing to note is that the forearm is pretty wide to accommodate the gas system.
Unfortunately, owning it was not without issues. Right out of the box, the cap on the gas ferrule was cross threaded. It was clearly missed in QC and Remington sent me a new barrel immediately. At round 4000, a retaining pin on my bolt came apart and tied up the gun. They replaced the bolt assembly, hammer, and most of the springs in the gun. I had it back from Remington in under a week. The last time, something in my trigger group broke and it came apart. I sent it back to Remington and it was fixed and back to me in under a week again. This was enough for me and sold the gun at this point.
As much as I liked the gun, it wasn't worth the trouble to me. I know others have had great experiences with them, but unfortunately I didn't. There is a monster thread over on shotgunworld.com with just about anything you needed to know about the VM. If you do end up buying one, I would purchase new as to get full coverage of the 2 year warranty. Also, make sure to send it in for the free inspection and cleaning.