We stayed at Colleverde for 7 nights and I can say it was the best deal we could've made for the money we payed. We came by car and we had our own tent. The place is really nice. I especially liked that it is very green and has lots of trees. Me and my husband we also enjoyed the pool - a great relaxation method after visiting a near by city.
Some of the things we didn't appreciate as much (thus the 4 starts instead of 5) - the wifi is not free (is costs 4 euros/day, or it can also be payed by hour) and they only have a few washing machines and no drying machines at all. So if you wash your clothes, you have to hang them around your tent.
We took the car every day and visited cities in Toscana - Siena, San Gimignano, Cortona, Florence, Certaldo. We even went to the beach one day.
I would definitely go again and I recommend it.