Might I venture to suggest, substitute Warwick for Cambridge & you might have a more interesting comparison.
Whitby is all that people have said except that you may have got the impression it is all participation. Apart from the odd workshop I rarely participate. There is a wide choice of concerts to be seen from midday to midnight, but few 'Big Names'.
Warwick is a large on site festival with everything there and a good balace between big names & club stalwarts. Given a choice I'd still go to Whitby.
Fylde is pretty good too.
Cheers
Les