The two smaller jars developed some really funky smells and some nasty gray mold. I think some clostridium took hold in those, so I tossed them. I've read that if fermenting veggies get mold you can just scrap it off, but the smell was pretty rank so I didn't want to risk it.
The big jar has been chugging right along though, with no mold and just a pleasant tart aroma.