When you don't have it, it obviously sucks. The impact of
Genie+ to standby lines looked similar to the old FP+, so longer waits, but you don't have the 3 (or more) free passes like in the past. By 10 at the Magic Kingdom lines are already too long for me: 40 minutes for It's a Small World might not be much for a first time visitor, but I've done it countless of times, it's not worth a 40 minutes wait.
And when you have it it's frustrating.
First of all, it's buggy, even more than
MDE used to be. I had constantly problems with the Tip Board (where you book a pass) not loading. Guest services couldn't help either. I had to keep two phones open with different accounts to try and book Slinky, and luckily I did that, because otherwise I would have waisted $60 (Slinky books in seconds for the whole day).
A few of the problems may be easily fixed soon. For example, I'd like to meet the person who thought starting booking at 7am is a good idea. Especially when it's Epcot day and the park opens at 10, why ask a turist on vacation to wake up at 7 to book a pass or a boarding group? In
Disneyland you can start booking as soon as you enter the park, it looks like a better way.
It's frustrating you cannot chose a different time. If you are given 12:30 for the pass and you have a dining reservation or another pass at that time, you cannot choose a later time, you have to wait and try to time it right. And you have to set alarms so that you remember to book a new pass after 2 hours, currently there is no way to know when the next pass will be available.
People who were looking forward to it, hoping for a more relaxing experience: forget it! It's night and day from the ease of use of the Universal Express Pass.
And all of this and it doesn't even include the best attractions! You have to pay separately for those.
The only park where it works is MK, it has enough good rides to give enough value during the day. At the Studios, Slinky goes in seconds and if you're not super fast you'll get a return window in the evening, if that. That means you can book a second one at 11:00, when most headliners will have a return time in the evening as well. And then that's it, by 1pm you'll get Muppets or Start Tour.
Animal Kingdom and Epcot don't have enough rides to make a purchase worthwhile. I can see how it can work much better at Disneyland, with so many more attractions, but in Florida it's mostly frustrating.