Product review (4 stars): Good kit overall...may have too much left over, but not enough of others...completely dependant upon your install requirements.
Has everything you will need, but...
  1. For my particular install, I needed 50ft more of the furnace wire, which ran me around 9 bucks at the local big box store.
  2. Again for my install, I believe it was a bit overpriced overall, but again I did not price out each article that is included in the kit separately to ensure this.
  3.  My suggestion would be to, install your humidifier and the controller, then measure out what you will need to make the  final wire, water and ductwork connections.  That way you can buy exactly what you need.  I had a lot of left over materials after my install, which I will keep for later projects, but its' something to keep into consideration.
  4.  I understand that this kit is a 1 size fits most and it did have everything I needed to finish my install...so it's not bad.
  5  I would also suggest they include some metallic duct tape to seal of all of the connections and I also used it to tape all of the wires to the plenum for a cleaner looking install.