I just got back from a 1 week trip (6th-13th). Let me start by saying I can see how G+ would not generate the same successes if the parks were any busier than they were (highest TP park level was a 5 for EP, most of the rest ranged from 1s at MK to 3s at HS). But I enjoyed using G+. Like some other users, I did my homework prior to leaving (thanks
@lentesta) and employed some of their strategies (Becky's columns at TP were invaluable). Monday at HS I golfed in the morning, and then via stacking was able to attain LL passes for ALL major attractions. I had so much time available I was able to see the Mickey short movie, and saw One Man's Dream twice (I fell asleep during the first viewing lol). I did both stacking and book, tap, book and both worked well for me. I am usually on my phone anyways as I use the Lines app to follow touring plans and I am giving them data anyways. With G+ I didn't think I was on it any more than I usually do.
Did not use it at AK, but both MK and EP days. I was on the fence about using it at EP (I did buy ILL for GotG), but the time savings I did realize for the attractions I did get LL for (primarily Remy and TT) pushed me over the top. I wasn't planning on using it at MK yesterday (go home day) as I planned EE the park, but I decided to sleep in and then purchased it. I was able to get 4 LLs for my short visit (10:00-4:00) and felt I wouldn't have been able to do what I did without it. Maybe I could have, but I know I saved at least an hour of wait times with it.
All that said, I was a solo traveler who was savvy to all the strategies and tips to maximize use. I was there during the lowest attendance time of year (according to TP). Where folks would be lucky normally to get 2 of the big 3 at EP (Remy, Frozen, TT), I was able to get all 3. Genie+ worked for me. However, I can see how it would not be a value proposition for families, or for busier times, and those that I did see use it did not seem to grasp how to use it (based on what I saw while in the parks). I think I would be singing a different tune if my wife and I went during our normal time (early December). Paying for it for one person per day wasn't that bad, and I was getting good value from it (if calculating cost per attraction used). Paying for two, and not using it nearly as much (my wife is not a parks commando like I am so we would not be as aggressive) would definitely dim the cost/value proposition.