We thought memory maker was worth it, dare I say a good deal, for the length we were there. Worked out to be just under $15 a day for us when we broke it down like that.
If you're there for a longer trip, meeting lots of characters and/or planning to buy ride photos and meal photos then I think it's worth it. If you only want a couple photos here and there you'll be better off buying them individually. IMO the individual prices are very high, especially for ride/meal photos, but if you only want a few the cost is much less than memory maker.