In reply to a lakeland climber: I reckon it's tougher than the dragon back. It's not a stage race, so if you are planning on winning it rather than just completing it you can't afford much sleep. Imagine day 3, no sleep, blizzard, middle of the night and having to decide if you are going to stop and pitch your tent and loose the race or keep going to the next check point to escape the conditions or just have a little sit down on that rock - with obvious consequences if you fall asleep.
The wrong decision could be fatal. The dragons back might be long and tough, but it probably won't kill you.
This year there was a small field of about 25 people I think and most of them dropped out on day 1 in near perfect conditions - only about 3 people finished the race. Suggests it didn't attract a very high quality field, so I hope if the OP is wanting to test himself against the best ultra runners in the country he isn't dissapointed.
Andy