I grew them "successfully" for the first time last year and I'm a pincher!! I got some nice ones. I grew mine right from a whole one bought at the mexican market. Never been able to grown them from seed before...just plopped a whole one in the soil and soon had more than I knew what to do with!
They can get quite big, too but never had any issues with pests onceit was established. Just cooked some up tonight, too!
I am not sure what they are but minemost often have worms in them. I have tried different ones. I decided they take up too much room to have wormy ones. Love them though