We did Photopass last March. I took tons of pictures but always let the Photopass person take them as well. The first time you get one taken, they will give you a plastic card (the Photopass) and you can hand it to the photographer every time you have a photo opportunity. When you get home, you enter the number on your photopass on the Photopass website and have access to your photos to view, share and order copies if you want.
When I got home, I developed all my film and then looked online at the Photopass pictures. I only ordered one picture because almost all of mine came out great. The one I ordered was the most perfect picture of my daughter with Cinderella. They are both looking right at the photographer. If not for Photopass I wouldn't have such a wonderful picture.
The best benefit to Photopass in my opinion is that you can share the photos with anyone online. I sent them to my family and friends and it was great.
The one thing I am doing this October when we go is having our family picture taken in front of the castle a few times, even on different days. We've had our picture taken on two trips now, and every time my DH closes his eyes, and in one we had taken on the last day of our trip, my eyes look so bad because I was exhausted.