Pros: Durability, Ease of Use, Effectiveness, Overall Quality
I love the idea of the Double Stuff, and it's a very high quality stone, but I prefer two separate stones so I have two sharpening surfaces per stone. The first Double Stuff I purchased, the glue gave up and the stones separated. I cleaned the glue off, and Gorilla glued them back together. Shortly after, I regretted doing so. Eventually I bought a 303F and a 303M separately and carry them together in the same pouch with a small strip of leather to keep them from grinding and clinking against each other when I'm on the move. It's a wonderful deal, two $20 stones for $32! I just prefer them separately. If you want the two glued together, this is an amazing deal, just be prepared to glue them back together in case the glue fails.