I think that these work just as well as Greenies and are less expensive. They also offer coupons a lot of time which make them even less expensive. Last week they were buy one, get one free at PetSmart so we stocked up :)
I think they were fairly well and are certainly less expensive! I bought these to replace the more expensive ones we had been buying, and my dog didn't seem to notice a difference, but his breath sure smells better!