Depends on the size of the dog. For smaller dogs I prefer a rechargeable (battery operated) Dremel. They only last a couple of years or so, but you can pick one up at WalMart for less than $25. So it's not a huge expense. The plug in Dremels are IMO too powerful for use on small dogs. If you have a larger dog with thick nails you probably need the extra power. Either of them can work for medium sized dogs, but I usually prefer the rechargeable Dremels for those dogs. I'd rather spend a few extra seconds per nail with a less powerful tool and have more control. The trade off is well worth it to me.