I used one for years on and off,( I think I still have it somewhere), they are good, but I find boiling dicroclean works as well for most stuff. To drive out really tough grease one can heat a part to 550f or so without damage and for rust a litte bath of dilute muriatic works well. I can get rusty greasy cruddy ancient old parts clean enough for plating, polishing or any other finishing in short order with a combination of these methods.

All the best,
Barry Lee Hands
http://www.barryleehands.com