So did a Disney run last Sunday (a pretty busy day) and something to share:
1. There are many bugs with the system still. Especially when you try to book a new
Genie+ reservation and you are not eligible yet, the reason given seems to be powered by a random number generator...
Also, whether or not you can cancel a Genie+ reservation (i.e. whether or not the "cancel" link exists on the Genie+ reservation page) is like determined by a random number generator, maybe an Android specific bug?
2. If an attraction does not have any desirable time slot available, keep refreshing and you may get one later. During the morning when I was in the queue for FoP (9:15-11:15), I wanted to get a G+ for Safaris (had a G+ reservation for SDD, so can only get a new reservation at 11:00). I have been watching the return window for it, and while generally it was in the range of 2:00pm+, eventually I secured one for 11:25. And during the Safaris I tried to secure a G+ reservation for Test track, while the return window was generally in the range of 6:00pm+, I eventually secured one for 2:20pm.
3. I saw some posts saying that Disney intentionally posted wait time that was much longer than the actual wait time to encourage purchase of ILL, it was not my experience. At 9:15am the posted wait time for FOP was 65 minutes while I entered the pre-show room at 11:15am...
4. It is not true that if an attraction goes down, everybody's ILL is automatically extended to the end of the day. Actually for my Remmy ILL (the app was a little bit confusing -- as basically all options were grayed out, I just thought that it never came back up), I went to the customer experience umbrella, and the CM said something like "it is your fault, but let me make a one time exception and extend it".
5. Value of Genie+? You can not compare with the past. In 2018 I was once able to secure 4 fastpasses for FOP in a single day by refreshing. Well, I have to admit that it was sort of unfair for other guests... Now, you may get many G+ reservations for some C rides in MK or Epcot or 2-3 rides in the other two parks. But think about it this way: that $16 saves you maybe 2 hours of park time, I guess it is still worth it to some extent.