My good friend has one of them. I havent shot it but he was playing with it while I was shooting my handgun one day and he put about 300-400 shells through it no problem. The only thing I think he ever got mad about was once he disassembled it and couldn't get it back together. He spent 8-9 hours before he figured out what he had done wrong by watching a youtube video.
I got it in. First day out was disappointing. After the first shot, the bolt release button pin almost fell out the bottom of the gun. After looking into it, I don't think Mossberg installed the clip that retains the pin from the factory. A call to Mossberg and a new clip is on the way. I put some tape over the pin to try again. I shot 100 rounds of high brass shot and slugs to break it in. I had 1 light primer hit that I later loaded again (and then fired). I tried 25 low brass 7.5 shot and had no issues. I am happy with the gun so far and can't wait for another 3 gun match to see how I do.