If you will be doing character meals where photos are taken, but sold separately then yes it can be a very good deal. With Photopass+ you also get a stock photo CD which can be great for scrapbooking & background photos.
I am choosing against getting Photopass+ because we are not doing any of the thrill rides and only have 1 character meal (Chef Mickey's where the picture is with a plate and not actually Mickey). My 2 yo son also often does not want to stand in line for pictures, so I don't want to end up spending $149 only to not end up with more than a couple photos.
Photopass+ is non-refundable. However, if you preorder the regular Photopass you have 90 days to request a refund if you decide against getting the photo CD. Our plan is to preorder the regular Photopass, have as many pics taken as possible, and then hopefully keep the order. However if my son does not cooperate, gets sick, or if for any other reason we don't have enough pics taken to justify the cost I will request a refund.