Last year we went on a cruise and were not going to be able to check in at the 24 hr mark, so I got them. I ended up buying them for the flight both ways. We had BP numbers in the mid-20s, but were actually one of the first on the plane on every leg. We loved it because we were able to get the emergency exit row on each segment (DH has bad knees and they really hurt him when we we fly, because it's so cramped).
I just bought them for our July trip to WDW because there are 6 of us traveling together, including a 27 mo old. I figure this way we can get on early, so hopefully hubby can snag his beloved emergency exit row again, and our daughter can get the row behind it that is so spacious so she can get the car seat in and out easier.
That's what I'm hoping for anyway.....