I'm a big Noble Knights fan – if you want to learn to play the deck or are looking for a new fun and pretty competitive deck – pick this up.
If you want to play competativly or at local etc, I suggest picking up 3 because you will need 3 copies of some cards like Noble Knight Medraut and Merlin for example. Youtube is a great resource for learning to build this deck and getting better at YuGiOh!