These work good in places that are too thick for a string trimmer but not heavy enough to require a metal blade cutter. I really like them for medium duty brush cutting. They are the best of both worlds but also the worst of both (string and metal). Hitting rocks, rip rap, metal, thick wood, they will wear faster or just completely break. You'll know when you broke one, your unit will run wobbly. Easy enough to change out, though. With all that said, I give them 4 stars because they are great for certain applications and all-around pretty good. The company is top-notch, they are USA based and they will answer any of your questions.