did it two years ago (the wet year) and it was really tough...partly cos of the rain/mud for 5 days. But we'd trained, and it was do-able..
am doing again next week! the course has completely changed - it's considerably shorter (390km vs 550km) and less climbing (12K vs 15K), but is apparently alot more singletrack and more of it is rideable. I'm suspect it won't be any easier this year, even tho each day is shorter....I suspect being more technical will take it out of you just as much as a long fire-road climb.
I'll let you know in 2 weeks!