It is a good deal...
and as the pp said, the 4/3 is a bit better if you are going to use all the free nights. We are going for 6 nights in March and after pricing it out (yes, including all meals since we had added the
DDP) it was nearly $500 cheaper for us to use the PIN code (and get park tickets through the Princess 1/2) for POR... and then we decided to do a split stay with the PIN and got ALK for a couple of nights and still came out cheaper than with the buy 4 deal.
Really, it all depends on your total number of nights and where you will be staying...
YOu can call Disney and heave them price out the different offers available to you - pin and 4/3 - and you can make your choice. I would leave out the DDP on the 4/3 deal for price comparison purposes since the PIN in room only.
Good luck!