I purchased these from my local airsoft store rather than here, way before they were available on this website. Overall they're an excellent alternative to more expensive shells and a great choice if you use a lot of grenades. They're lightweight, durable, and simple to operate and clean. I do have a few complaints, but they're very affordable grenades, so I can't split hairs.
Simple to operate
Simple to maintain
Cover to keep bbs in shell while running around
Holds decent amount of bbs
Cap can be fired as "grenade"
Plastic upper half
BBs fall out easily when cap is not on i.e. when the shell is in the launcher
Need to be lubed frequently. The simple firing system allows lube to be blown out with the gas.