We'd highly recommend Highfield, its a Best of British site. It is a short drive to a park and ride to Cambridge, a bit out of the way for shopping but there is a little area about a mile away with some very quaint shops (butchers, gift shops, cafe etc).
We visited Cherry Hinton CC site and were very glad we hadn't stayed there. Very cramped and toilets in need of a revamp.
Highfield is spacious, split into three fields, lovely clean toilets/showers and we always return. Loads of room for children to play, a little play area etc. We usually ask to be away from the childrens site on the top field which is beautiful and the birdsong is second to none.
Houghton Mill is another lovely site although difficult to book into. It is within walking distance of a little village shop, a couple of pubs and has a beautiful little church etc. You can also walk into St Ives from here but it is a bit of walk - you'd probably end up bussing back!
Hope this helps.