Its perfectly legal, just don't take it through the airport security.
It's a great little backup knife. I keep mine in my wallet. For any serous cutting though, it is not super effective. It takes a moment to open up and is not the most "solid" thing ever due to it's foldable nature. I think that it would hold up fine in the long term, but for constant use you really need to get a regular knife.
My main issue with D&D selling it is that they have it marked up $7 extra for no good reason. Get it for $20 at Knifecenter or elsewhere.
