I am quite sure they saw big gains because they are comparing it with a stock motor. Conventional valved Ford 5.0's have been built that make even more power then that.

It is very easy to make something that will improve a stock Ford's performance. When they bolt it on an F1 motor and start winning races, then I will believe. Yes, poppet valves are old tech and have some major drawbacks but they are still in use for very good reasons. No one has as yet figured out a way to make any sort of rotary valve with a non linear type motion. Until they do, poppet will rule.

I see the best bet for future 4 stroke innovation being electro-mechanical valves. Keep the poppets and their motions but ditch the cam shaft.