Since FPs are free, of course they're worth it. Just know how to use them. For example, Don't get a FP is the stand-by line is 20 minutes or less unless you know you'll be wanting to ride more than once. Once you get a FP, don't just hang out by that ride until it's good. Go to another ride, eat, shop, see a show. You don't need to get back to the ride the second the FP window opens. In fact, you don't even have to come back during the window. You will not be allowed to use the FP before the window opens, but there's no problem using it after the window is technically over.