In an interesting and thorough article in the Telegraph last week David Hughes  argued that history tends to favour the inexperienced outsider in leadership elections, and the following day Simon Heffer  also encouraged Miliband to go for it. I particuarly noted this sentence in Heffer's article:
"Mr Miliband should not imagine this will be one of several chances he will have to lead the Labour Party."
It's strikingly similar to the advice (which seems to have been taken to heart) that I humbly offered Barack Obama  prior to his entry into the US presidential race. Regardless of my (hitherto undecided) personal preference for the Labour leadership, I'm inclined to agree that if Miliband holds any ambition to be Labour Leader and Prime Minister then he should not tarry.