Next time you are in your local shop, get them to pull apart that fabarm and have a look at the guts. I recently purchased a Martial Pro Forces 14 inch fabarm pump, and was amazed to see how much like an 870 it looks like on the inside.
Their big "imporovement", the return spring on the action transfer bars, I just could not get used to and has been since removed. How does the gun handle? Not bad...but not as good as some of my cherished 870 wingmasters.
One thing I do like about it though is the meaty action release button....I find it more accessable than those on my 870s, however not enough that it would be the gun I would grab in a pinch.