Apologies in advance for the long post...
I think it depends on what you spend your money on, how you pay the card off, and what kind of rewards you want.
To clarify, there are 2 cards, and both had the perks @
mousefreak described above (6mos no interest on trips, 10% off, etc.). As I understand it, the "regular" Disney Visa has no annual fee, you get 1% rewards on everything you spend, and you can only get rewards in the form of a Disney gift card.
The "premier" Disney Visa has a $49 annual fee...the different is that you get 2% rewards on groceries, gas, restaurants and Disney purchases. You get your rewards in the form of a Disney gift card or airline miles (not totally sure how the airline miles rewards work).
We've had one of the two Disney Visa cards for awhile. Having the "regular" sort of seemed like a no-brainer as there was no annual fee. I'm sure the interest is ridiculous but we always pay our bills in full every month, so that wasn't an issue for us. Recently we were able to pull up all of our old statements through Chase to see if the premier card was better for us. The Chase statements were already divided into spending categories (gas, groceries, etc.) so we did the math on what our 2012 rewards were with the regular Disney Visa vs. what they would have been if we'd had the premier Visa, subtracting out the $49 fee. The premier card won out (we would have gotten $50 or so more in rewards IIRC) so we switched to that one. The 2% back on restaurants and groceries is key for us (gas less so). We also have a Chase Freedom card that has 1% back on everything, no annual fee and 5% back on certain items depending on the quarter. Right now we like accumulating lots of Disney rewards because when our trips come up we're able to use those rewards to pay for our meals, so that's our primary card. We only use the Chase Freedom on items that fall in the 5% reward category (right now it's gas). I'm certain that there are better cards out there and that we could be getting better rewards, but this is what we prefer to do right now. Everyone once in awhile we re-evaluate like I described above (looking at historical statements)...if our spending habits or vacation preferences change we'll switch up our system.
There are other benefits to cardmembers...occasionally we'll get emails about Disney package discounts before they are released to the public. There's also discounts and early registration for the runDisney race weekends and discounts on tours at Disney. I also get emails for pre-sale events for Disney shows (was able to get tickets for The Lion King stage show before they went on sale).
As for store discounts, I have just started asking at each Disney store if they take Disney Visa or AP discounts...I don't feel like memorizing the list of places that do take them so I always ask.
TL;DR - it's not the best card out there, but evaluate your spending habits, read up on the rewards and figure out if it'll work for you.