We had professional pictures taken there in May done by one of the photographers. We had them done in Epcot World Showcase, before it opened - during the Flower and Garden Festival.
They came out good, but truly not any better than any other professional photographer. The photographer was good, knowledgeable, and professional, and the pics came out okay, but they were all posed, traditional pics. We were disappointed that he didn't do a better job of staging us, many of the shots could have been much better if he had repositioned us a bit and such, so many of the locations were lost because of that. We had to do alot of the staging ourself, so it didn't seem like he had a good eye for that. That was a bit frustrating, because I like having a professional helping with that. i must admit that the last time we truly had prof pics done was at our wedding less than 2 years prior this, and our photographer was a journalistic style with an incredibly talented eye for angling, details, and creative positioning - so this was a big change for me.
We ONLY chose to do it because we all live diff places, and had one big vacation at the world together, and it was an once in a lifetime opportunity to have pictures made. I looked into other area photographers, to have pics done somewhere there, but it was just too hard to take time off our vacation to do that. This was easier for us, though pricey.
If you contact them, they can give you an online address and password in order to see sample pictures. They are the same photographers that shoot weddings/honeymoons, but many of the family pics we saw examples for were grand gatherings and LOTS of people.
If you're there with people you can't get pics made with otherwise, I'd fork out the $ for it. But if you just want family pics done, I'm not sure I wouldn't just find a great studio in your area that can do creative pics in a format that would include variety of settings, clothing changes, etc. All these pics are color (not my fave), as well. The reprints are pretty expensive, as is the setting fee, but of course it is Disney =)
We weren't interested in having specifically Disney pics, either, so that might be diff if you truly want that. We just wanted gorgeous pics we'd hang on the walls, which is why we did the World Showcase with the flowers =)
There are loads of great locations there, they can tell you what the best places are. I saw some made in the hotels, on the beach, in the park, etc. You really don't have time to move locations, though. We thought World Showcase offered enough variety in location... between the diff architectures, benches, bridges, etc.
Also keep in mind the time of day you want it in - we did late morning, and the sun was really too bright. We should have done it much earlier, or at dusk.
Let me know if you have any more questions!