I didn't mean that the 319 is not a good sewing machine. It's a very good strong machine. I just meant that some ebay sellers tout it as being "Industrial strength" and ask hundreds for them.
They were made as home machines, and will do some heavy sewing, but they are not made for a steady diet of heavy work.
I learned this on some old sewing machine groups, not because I have experience with them. Some sellers say the same thing about modern machines with plastic gears, too. It's dishonest, and then folks who don't know any better parrot the same things.