Both guns have been a bucket full of problems. I love Mossbergs, the 500 is my favorite gun. I know 2 people that have experienced bulged barrels with the Stoeger. I have heard of other bulged barrels. I can't provide you with an online link to prove it. Just call Durham County Wildlife Club in Durham, NC. They are open to the public on Sat and Sun.
The Mossberg barrels aren't bulging but people are having other problems with them. As I stated earlier I love Mossberg and give them the benefit of the doubt until the problems are overwhelming.