It's worth is totally subjective. I had it in November. With just my sister and I, we had over 200 pictures - posed and magic shots. Plus there was also the video from the Mine Train and some of the Magic Shots were animated. You do have to take the time to stop at the photographers so if you don't want to spend time doing that, it wouldn't be worth it. I thought it was worth it enough that I'm also getting it for my September trip as well. We're even planning one day as a "picture day" so we can get more photos and also so I can take the time to take my own photos.
To get it at the discounted rate, you need to purchase it three days before you activate it.
You download the pictures from the Photopass site. I believe, for an additional fee, you can also get them sent to you on DVD. The downloads were perfect for me.