My wife and I have Disney Visa. It's our only credit card.
We pretty much charge everything we can to it. Groceries, gas, bills, household items, trips, airfare, etc... If it's chargeable, we charge it.
We also pay it off in full every month. Chase has yet to collect a single dollar in interest from us.
We usually earn about $450 reward dollars each year and we use this pay for all of our dining while on vacation. Found out last trip you can pay for parking with the rewards card, so we paid for that with reward dollars too.
The free Disney Visa photo-op is nice cause you can luck out and good a good group of characters. The first year (2009) was a nice one-on-one with the characters. They only had only family in the room at a time, This past November it felt very rushed though. While you were photo taking, the family behind you was already being brought into the room. So not sure if they changed the line flow, if it just depends on the CM's that day.
But anyway, we're not big into rewards, airline miles, etc.... with credit cards, so we've been happy with our Disney Visa cause it does help cover a good chunk of our vacation budget.
We've also used the 10% discount a few times at the Disney Store here and at The World of Disney at Downtown Disney.