In reply to yorkshireman:
I'm glad I did UTMB first and saved the TDS as something to look forward to. It's often considered the poor relation because it's not the big name but I'd compare UTMB to the London Marathon on trail. Being stuck in a long queue for most of the race. Unless you were really forecful and prepared to barge past lots of other runners then you took your place in the queue and accepted that was what it was. Getting in and out of CPs swiftly got you to a different place in the queue but I can only remember a couple of occasions where I had any sense of space on that race. I really didn't enjoy it much as you can tell!
The weather was a killer the year I did it too, I remember coming up out of Cormayeur and every step was a real battle. When I got to the CP at Refuge Bertone my heart rate was so high I really started to worry! I laid down in the shade of a hut and stayed there until my core body temp had lowered. Not a pleasent experience!
Last year the weather started like that but then turned to heavy rain which cooled things down a bit but turned the trails to rivers of slippy mud. I had to laugh when a group were on my shoulder following me down the last descent, when I offered to let them past they said no, they were following me because I knew where to step to stay upright. I replied 'of course I do, I'm British, we always run in the mud!' That certainly lightened the mood!