Miliband was educated at Primrose Hill Primary School, Camden, Featherbank Primary School, Leeds, and then Haverstock Comprehensive School in Chalk Farm, North London. He completed his A Levels and was a violinist whilst at school. As a teenager, he reviewed films and plays on LBC Radio's Young London programme as one of its "Three O'Clock Reviewers", and worked as an intern to Tony Benn. Miliband read Philosophy, Politics and Economics at Corpus Christi College, Oxford, where he was also elected JCR President. In his second and third years, he dropped philosophy, and was awarded an upper second class Bachelor of Arts degree, then went on to study at the London School of Economics, where he obtained a Masters in Economics.
Sounds pretty normal (but smart enough to be PM) to me.
Gordon Brown? Ed Miliband (And before then: Thatcher, Heath, Wilson, Callagahan... In fact posh PM's have been a rarety over the last 40 years)
In answer to the question; as much as I find Boris entertaining I wouldn't want him as PM. For one thing he is far more right-wing than people realise, secondly he may be good fun but that does not make him a good PM, thirdly he has no actual achievements to his name and, indeed, as Mayor of London hasn't actually done much (And his own iniatives have failed) and fourthly I don't want someone whose moral track record is a sketchy as his as PM.