Think about it, there are just too many contributing factors:

Distance
Climb
Descent
Steepness of climb
Steepness of descent
Terrain (in all its multitude of guises)
Weather on the day
Weather in the weeks leading up to the race
Time of year

When I ran the Edale Skyline route, admittedly without the first climb out of Edale, I found it a nice undulating route from an ascent and descent perspective, miles easier than the 3 peaks from that point of view. On the flip side though, the terrain was very hard going for two thirds of the circuit, miles tougher overall than that of the 3 peaks I'd say. Also with Edale you're running high for a long period of time so if the weather's bad, its going to be very, very bad.

They're both equally evil then