We went last year in June, so I made my FP before FoP actually opened. Because no one knew how awesome it was, it was an easy FP to get. Once we rode it, I instantly regretted not making a FP for it on another day. So, chances are, you will want to ride it twice. However, even though my family would have loved to ride it again, we weren't willing to deal with rope drop madness or an hours long wait, so we just rode that one time.
You have to show up about an hour earlier to successfully RD FoP than if you want to RD Na'vi. My family hates crowded rope drops, so for us, it's not worth it. But if you're game, you certainly won't regret riding twice.
I managed to get a 4th FP for Na'vi, so we never rope dropped anything. We won't be riding Na'vi again unless there's no wait. It's just not our thing.
Easywdw has some great posts about doing rope drop for FoP. Google easywdw flight of passage rope drop, and you'll find posts for a 9:00 open, an 8:00 open, for EMH, and for just doing Na'vi.