I have an account with TouringPlans.
I think the main benefit is that you get a really good idea of which rides to ropedrop and FP+. That way you're not wasting a FP+ on rides that don't need one.
I did create my own personalized touring plans with the account even though I know wait times can vary from day to day. You can't take things into account like rain or rides breaking down, but that's just life. However, it does give me a rough estimate of what I can do each day.
Also, there are other benefits. They have a reservation finder. So, if you're having a hard time finding a reservation at a popular restaurant, you can just put your preferred date and time, and they'll check the availability every so often and text you when it's available.
They also have a Room Request Fax. So, say you have a room booked at Pop Century, but you want a room overlooking the lake or a room that's in a "quiet area," you can put this info in the Room Request Fax, and TouringPlans will fax it to the resort at the appropriate time (4-5 days before you arrive). It's not guaranteed that Disney will fulfill all of your requests, but it's a nice little extra.
They have a Historical Crowd Calendar. So even if you question what the Crowd Calendar "could be" for November 2018, you can actually look at the Crowd history all the way back to 2009. They even have hour by hour (minute to minute even) of historical wait times. So, you can see that on Nov. 15, 2017, Flight of Passage had a wait time of 180 minutes at 10:00 AM.
Anyway, I love the site. It gives me a really good idea of what to expect, what to ropedrop, what to FP+, etc. I think it's worth the $$$ in my humble opinion.