I like the official Disneyland App. It has ride wait times, current FP return times, character and entertainment schedules, etc. I've used it on several trips now and have found that the wait times match with what is posted at the attraction entrance for the most part (there is about a 5 to 10 minute lag in information updates).
I used to use MouseWait and DL Waits and they were okay. As with most of the free apps, they're only as good as how often someone in park opts to update the wait times. So sometimes, they're really accurate and sometimes the information is hours old. Mostly, I've stopped using them and only use the official app at this point.