We love it and find the WDW plans pretty accurate. We usually end up finishing ahead of the schedule. We always do a personalized plan that is optimized. We have used them for 3 WDW, 1 DLR, and 1 Uni visit. Two of the WDW were with FP+. The only problem at WDW that we have had was our first visit. The first Festival of the Lion King show at Animal Kingdom started later than TP said. I think the problem was that I hadn't re-optimized in a while, weeks or months, so my plan didn't have the latest schedule info. I now usually re-optimize or at least evaulate my plans a day or two before the trip, to get the latest data and schedules. Play around with the evaluate and optimize and try different plans for the same day to see what works best for you. I especially do this to try out different FP+ times, but I usually end up going with their suggested time for my FP+.
The Lines app is great too. If you paid the subscription, then you can get it. It has posted, expected, and reported wait times, as well as available FP+ times. It also has dining menus, which is really convenient for QS.
My best advice is to use some common sense about things. Nothing is perfect. If TP has you getting to a show or FP+ later than you want, then skip a step or two and do the show/FP+. You can just come back to what was skipped. The time difference is usually so minimal that it's not going make the plan worthless. If you want to shop or go to the bathroom, do it. There's no Touring Plans police that's going to call you out for not following it exactly
Also, use the listed arrival times as a guide to how things are progressing. Don't freak out and get uptight if you are a bit behind. It usually works itself out in the wash.
Have fun and good luck.
