Over the years i've camped on site and glamped at almost every option, worthy view, tangerine fields, love fields and one i dont recall the name of as well as both campervan fields and the last two on site.
The first using camplight on pennards hill and last year camping in Baileys.
Off site adds A LOT of walking to the day and prevents nipping back for a rest. most of them are still just a tent (could be a nice tent mind) with a little more space. The bonus of a shower is a good one but in all honesty not a deal breaker.
if i was to rate them i'd say a campervan wins for comfort then on site camping with a good camp bed, pillow duvet or bedding of choice.
Getting set up on site is the only poor point but once done is great.
Being able to go back and rest for an hour or so is the best option. The heat last year (was amazing) made a rest in the afternoon essential for me.
If the wife comes this year i'll use a campervan. If its just me and my daughters then i'll camp on site and save myself the money and the extra walking!
Hope this helps