Pros : These are a must have for glassline pens. There are 3 different sizes provided. They allow you to get intricate details, whereas squeezing directly from the bottle would almost be impossible. The cleaners make clearing the dried paint from the tips so easy. I ordered extra tips just so I can have different sizes for each color handy.
Cons : It would be nice to have a cap that would top off the tips. When working with the tips the paint will dry quickly if you are not constantly using the product.
Other Thoughts : If you really get caked in paint in your tips, nail polish remover works great. Just soak them for awhile and you'll be able to get them clean.