Absolutely agree, was far harder than I had thought it would be, fantastic weather though, for all the times I've been around the area I've never seen ti so clear.
The plan for yesterday was to take it very very easy all the way around, I was running with a freind who's doing GUCR in three weeks so we'd agreed to just do a very gentle training run and not race at all. The route kinda took it out of our hands though, there was no way that wasn't going to beat us up 
Very gnarly indeed, very little of it I found was comfortable running,even the flats and gentle downhills were on such rough and rocky tracks that they really needed you to take it easy. Brilliant fun though.
Agred with the assessment of Cribyn, the first part was tough but when you came over the final false summit to see the peak rise straight up I had a little 'feck me' moment.
Further along though, not sure what descent it was but it was the fairly good path near the end, mostly crushed gravel,that was brilliant, really went for it on that and according to my Garmin I went under a four minute mile!