I have Pedi Paws, and use it regularly.
My dog hates to have her nails clipped, but will tolerate the Pedi Paws better. She doesn't really like it, but at least she doesn't try to bite me now.
For my dog, this was well worth the money, and yes it does smell like burning at times, but only if the nails are a little longer.
Getting replacement sanding disks are readily available, I bought a large box of them, so it should keep me going for awhile.