I tried all the parts and this is what I found.
The main callus remover works great!  It even comes with a replacement roller.  The little tools attach to the side and as another reviewer mentioned, they do not snap in so may fall out if using at the wrong angle.  However most of them work great.  I love the hard metal one to remove dirt under my nails, and the cuticle remover and polisher are very effective.  My least favorite was the nail filer because I prefer the traditional method of using a hand held nail file.  It came with 2 drawstring bags to hold all the accessories along with the machine.  What I like best about this is that its so easy to work on my nails now.  I can literally do this while sitting watching TV, instead of having to go to a nail salon.
Rating: 4 stars