I prefer to do dadoes with a router for a few reasons. For large panels or heavy stock, it's easier to take the tool to the work. In using a hand held router, you can see what you're doing. Doing dadoes on the table saw require the stock to be held down throughout the entire cut. The blades are cutting into the face, which can leave some tear out, and you can't see what you're doing. Many stack blade sets don't leave nice clean bottoms.
So, I came up with a jig, which can be made any length, and clamped with an ordinary bar clamp.