At first my dog was scared to death of this and would not even let me get close to her. I kept trying over and over till she finally let me do one nail. she shook the whole time but she let me so it. The next day I was able to get them all done. I love that it is rechargeable. I would give it 4 stars for small to medium dogs. My dog is about 20 pounds and they worked pretty good. I am afraid that with a very a large dog they will not have enough power to do their big tough nails, but I may be wrong. I will try and see on a friends dog as soon as I can. As far as doing my dogs nails, I like it. It took me a pit to figure out how to hold it and when to stop, I think it will get easier each time I use them. I would say I am very happy with my purchase and would buy again. It recharged fairly fast.