Interesting bainspj. I guess if you're going to be critical then doing too large a -ve split is a sign you got it wrong, or that something was awry which is what happened to Mr B. He was in 2h45 shape when his quads seized early on, stopped and was about to DNF but jogged a bit and found his legs began moving again: hence his remarkable -ve split.
The other two (Riel and Nick) you quote look to be great stories though. Blimey. In the sub 2:45 domain Alexis Fuller, Nick Sparks and our own Ryan Snell have shown how it can be done. I'm hugely impressed Ryan. I wish I could have the self-discipline to hold back like that. I seem to do it in everything except marathons! Hats off to you.
Ryan I was just looking at your splits again and I may have missed some of this in the post race melee but that was a hell of a -ve split you did. Did you intend to go for sub 2h45 by running the first half in 1:23:30 or did you just feel good and know you could do it as the second half unfolded? And another question: who on earth was the one person who managed to go past you?!! You pretty much did a Paula Radcliffe WR type race there, albeit at 2:45 if you see what I mean. I reckon it's up there as one of the great thread performances.