I had a go when they ran it in December last year and it was quite a relaxed affair. The weather was pants, but thats what you'd expect at that time of the year.
The course depends on which category you enter. The loosely names Technical category uses the Whites Level trail and when I did it the Black run, Windypoint and Darkside we're timed. There is an Endurance category that uses part of the Skyline loop as well, but that had a timed uphill section so I avoided that one.
I'm not very competitive but I enjoyed the experience it immensely. I like the format, but they have had issue with the timing, but I didn't have any problems mine. I'm going to have anothe go in the summer. I see they're also running one at Glentress.
http://www.konamashup.co.uk/