Memory Maker is an amazing product and if you know how to use it, it can really enhance the memories of your trip!
You must first take into account the length of your stay. If you purchase Memory Maker a MINIMUM of 3 days prior to your tip, you get a discount on the price. You MUST be sure to purchase it a minimum of 3 days prior because the discounted rate does not include photos taken within 3 days of purchase.
In terms of price, think of how much each photo is to purchase on its own. Essentially if you would purchase 5 or less photos, you can get away with not purchasing MM and just having the photopass photographers take photos with your own camera. However, if you want more than 5, the MM is a good choice. Especially if you are looking to go to meet and greets and if your family likes to take multiple photos.
The best way to maximize your memory maker photos is to plan ahead of time the order in which you will take your photos. This way you aren't there stumbling over who is getting their photo taken. So if you want a few with the family and than some with just parents, then just kids, then all the girls, all the boys, then individual ones, have this in mind when you go up. It will make everything smoother.