DisneylandLinesTP is great for while you're IN the park, but it's even better for when you're NOT in the park.
Let me explain.
The chat room, close in feel to "lounges" of other unofficial Disneyland apps, is ripe with quality content conversation. Whether you're planning for your trip, wondering which walking shoes are recommended by DL veterans, or just want to experience more DL discussion to soothe your post vacation blues hangover, it's a great place to check and participate in.
As for the service it provides while you're in the park, superior to other apps in that it offers advice along with the wait times. A veteran may see that Indiana Jones is 35 minutes and realize that's a jackpot opportunity to go into stand-by if you don't have a fast pass, but noobs and even anxious vets will appreciate the advice that comes with it in their "go now" or "go anytime, wait time won't change" FYIs.
I also highly recommend the companion book, The Unofficial Guide to Disneyland, as it's the most entertaining literature on the park I've found in my seven years as an annual passholder. Thorough information on the parks and everything in it, comedic albeit dry commentary. 5/5 stars.