Yup, have just bought my ticket for second year running.
Ds was just 3 when we went last year. We also went with other friends so had, between us, kids of 2, 3 (x2!), 4 and 7. And even though it pissed with rain the entire time, we all LOVED IT.
I hadn't camped for donkey's years and ds had never done so. Can't deny it was a bit chilly and damp but it definitely wasn't stressful at all. The kids had a whale of a time and slept like logs at night - all that fresh air and running around.
The site is small and gorgeous, very family-oriented. It's like being in someone's really big back garden! There's a specific 'family' camping area I think but we just pitched with everyone else. It's quite a 'naice' well-behaved festival, no drunken louts...a fair bit of late-night bongo playing but that's festivals for you, I guess...
Great kid's area, puppetmaking, crafty stuff, shows, sciencey things. Lots of little crafty stalls - FABULOUS food (no, honestly!)
I would have no hesitation in recommending it. Ds can't wait to go back (and nor can I)
Go on, you know you want to...