memory maker is just the picture download package.
You can try photopass all you want for free, but you can't get the photos they take until you pay for them. The options to pay are per picture ($15 each, 1 day memory maker which cannot be prepurchased but gets you all the photos disney took for 1 calendar date ($59 I think), memory maker (unlimited downlaods) purchased at least 3 days before the first picture was taken ($149 I think) and memory maker (unlimited downloads) purchased after the trip ($169 I think). Also free downloads is included in annual passes now so that is an additional option to pay for the photos as well.
The pros is they are in the best spots and you can all be in the photo really easy and let disney take the picture. For things like character meals, it's really handy to let someone else do the photos while your enjoying your meal and the characters. They also have some extras you can edit into the photos as well as some animations and other things they can make appear in the photo..
The big con I see is they aren't the professional photographer part of disney and just interesting cast members or college program which may or may not be a photography major. With that said, 99% of the photos I consider to worth keeping so don't read too much into this. if they all sucked, nobody would buy it and disney doesn't want that..
another con is you probably need to wait in line for your turn to get your photos taken. I do regularly use them for those we're in the park shots. so
MNSSHP, I got a couple photos in front of the castle and down mainstreet where you could see the castle and decorations. We still take lots more pictures on our own, but it's nice to have someone take it for you and in certain places, the photopass photographers are the best spots.