There are a lot of pros and cons of staying in the campervan fields. I do it because my friends I normally go with have a camper, and I put my tent up next to them. I do like the fact we can just drive in and don't have to do the big walk carrying all our gear to the campsite, and can also wait until the big queue has gone before getting our wristbands etc. I also like that you get a much bigger space to camp, and as a Glasto veteran, the peace and quiet is rather welcome! But yes on the downside, the walk there and back every day is a pain, and you can't just pop back if you forget anything or to top up beer supplies etc.