I also have both of the aforementioned subscriptions. Plus one to WDW Prep School. (I've been planning for a while and was really about ALL the information I could find.) I like all of them for different reasons, but I don't think I would say any of them are necessary or even invaluable to my trip.
Touring Plans has been fun to play with itineraries, but if you're on Android, the app is OK at best. A straight port of a iPhone app. If you feel like you need to plan down to the minute, might as well give this one a shot.
Kenny's app is just a webpage, but that actually bothers me less the than iOS port of TP. I like the way it looks and behaves. I will probably end up putting my touring plans into this app for our trip.
WDW Prep School's planning tool includes pictures of ride vehicles, which is nice. But it really doesn't offer much that you can't get elsewhere and no app. I mostly got this one to support Shannon because I really enjoyed her podcasts.
So all that being said, easyWDW has all the information you could want, live wait times, and a great sense of humor all for free. The further in I got to planning (FP window opens in a few days), the more I relied on Josh's information there. He's also very active on the site forums and answers questions constantly. If I had to do it all over again, I would probably not bother subscribing to any other sites.