We typically don't order prints from Disney, we just do some borders and stuff and order the CD, then upload what we want printed to Shutterfly, which often gives out free prints themselves.
We typically order over 250 pictures from our vacations though, between photopass pics and our normal camera pics. If you're only planning on getting 30-50 pictures or so, this might be a good deal. I think we ordered the CD in advance and took the $50 discount that was given.