What's all this twaddle about Cameron being the only one of the 3 being labelled "posh boy"? Nick Clegg was born into a privileged background and has Russian nobility in his lineage, went to Cambridge etc etc.
Clegg no more stole the show than either of the other two - he had to be more combative than Brown or Cameron simply because he knows, as anyone else with half a brain, that the best his party can hope for is to hold the balance of power in a hung parliament, and in the public eye he's not as recognisable as the other two.
The Lib Dems can promise us the earth because they know fine well that they will never be in a position to have to deliver, that's the long and short of it. For example, he used the word "discipline" when referring to schooling. I almost laughed because that is a word, sadly, which no school teacher has in his/her armoury. Brown also used the word and was even less convincing about it than Clegg, if that was possible.
All 3 were so well primed that it was inevitable that a disaster for any was neither really on the cards, and it left me as I'd started when watching it - still confused and very undecided.