A friend and I recently decided to give glass etching a try. We had good results on most of our projects, but I had one 9×9 pyrex dish that did not etch at all. Several websites warn of this, but we had other ones that turned out beautifully, so maybe there are different types of pyrex? If you are going to try this, I suggest you do a test dot on your project to save you putting a lot of time into the design only to find it does not work on your particular dish.
It is a nice way to personalize a nice glass jar/canister full of Christmas cookies for gift-giving. We also like that it makes our dishes easier to identify at large potlucks!
You can also use an electronic cutting machine such as Cricut to design and cut more elaborate stencil designs onto your adhesive vinyl.