FotH takes 1:09, Barnstormer is 1:00. So both are very short.
I rode FotH 3 or 4 years ago with a co-worker on a business trip and it was very slow and boring. Halfway through, she turned to me and said, "I am going to put my arms up for something to do" Ha!
We had always avoided it on family trips (kids are young adults and love big coasters). This last trip, we decided to give it a try and ended up liking it. It felt MUCH faster than that first time I road it. We ended up riding it 3 or 4 times the days we were there - always with EP and very short, if any, waits.
I wouldn't wait more than 5 - 10 minutes for it, though.
I think it's pretty comparable to Barnstormer in intensity. The drop on FotH is probably slightly larger.