The codes can be very similar. Sometimes the pin codes are really nice. but in the end, which code is best really comes down to which is best for you based on your travel information.
If you have a family with 2 adults, 2 kids getting base tickets, and quick service dining, staying 5 nights (summer rates) -
Staying at a value
Pin code for 20% you save something like $130
Public code for 25% you save something like $160
Pin code for free quick service dining saves you something like $420
Disney Visa code (free kids) saves you something like $460
Public code for gift card had no 'savings' off rack rate, but you receive a $300 gift card.
However if you are staying in a AKL -
Pin code for 40% you save something like $675
Public code for 35% you save something like $590
Pin code for free quick service dining saves you something like $420
Disney Visa code (free kids) saves you something like $460
Public code for gift card had no 'savings' off rack rate, but you receive a $750 gift card.
There are many other things that will change what is a good code - like no children under 9 means no disney visa code.