I actually own one and love it. No feeding or failure to fire issues with a variety of target shells. I bought it because I was recovering from a broken shoulder and ankle after an accident and couldn't handle the full recoil of my Citori. I wanted a gun with adjustments so the Beretta and Benneli were out. I used the XLR5 for one season and after I learned to quit fiddling with the adjustments my scores settled in nicely.
There is definitely something different about the FabArm barrels and choke system as the get very tight well balanced patterns.
Fit and finish on mine is excellent, I get a lot of compliments on it and people who've tried it have all been impressed.
Early models had a very large palm grip which I've read was a problem for some with the trigger. If I remember correctly they actually gave people replacements stocks. Mine is a later model but it is still a big grip and I have the trigger shoe adjusted all the way to the back. But I have short fingers. Its almost as good as my Citori for feel.
It's not a light gun but it swings well for me and was a great sporting clays and skeet gun. All semi-autos in general are a bit of a pain to handle on the trap field but it was great to actually shoot.
Its very quick with doubles and I'm able to quickly get on the second shot because of not having to deal with the recovery from recoil. For me I found the using both the extra barrel weights help smooth my transitions but I suspect that had more to do with the years of muscle memory from a heavy recoiling gun.
I wasn't able to shoot very much so can't comment on the longevity but like you I've read a lot of very positive comments from heavy shooters. It seems like a very durable design. The Velocity model uses a slightly tuned gas system designed for lighter loaded target shells.