I prefer glass nail files on my nails because I find them easier to use and more hygienic than emery boards and because I recently broke mine I was in search for a new one.

I found the Quo one after much searching, I found the price a little steep but compared to the Revlon for $13.99 it was a steal.
The Quo glass file has 2 filing sides which was surprising since my last one only had the one side. It is about 5 inches long and has a black velvet storing pouch, it does a good job shaping nails and depending on how much pressure you use, it can take off a lot of nail or just a little .

The only thing I dislike about it is that it's a little plain looking, with an opaque handle whereas my previous one was blue, but in all a lifetime nail file (assuming you don't step on it )