The "+" of "MB+" is not much, however... there are surprising little things that happen when you have it, such as when you get into the line at Haunted Mansion after the stretching room. I won't say what it is as not to spoil it for anyone that might plan to experience it. And there are light reactions at other rides that are "fun." It's inessential, you won't miss it if you don't have one and you DO have to charge them every night. However, in a trip that already costs in the thousands I think tossing in an extra $40 on my reservation for a new MB+ is kind of irresistible to me. I've got 2 now, 1 each from my last 2 trips. If you get one, I think you definitely will want to get the little locks or strap holders because my mom's came off multiple times and she ended up losing it. It seems like the straps are a bit more rigid, maybe, and come unclasped a little too easily.