I have heard that Magnesium Stearate is not good. Although Swanson supplements are cheap, some people like them. I've been using the Back To Health MSM, and there are no added ingredients.

"Magnesium stearate is most commonly used in supplement manufacturing as a ‘flow agent,’ which helps ensure that the equipment runs smoothly and the ingredients stay blended together in the correct proportions." chriskresser website, /harmful-or-harmless-magnesium-stearate/

Some think it's harmless, some don't. I prefer to use bulk supplement whenever I can find them. They are cheaper anyway.