We had a great experience. Our pickup location was very close to our hotel and very prompt. Our ride was comfortable, with our guide giving us all the pertinent information before each stop. I can't give four stars to the trip because there was simply not enough time at each location, but especially Stratford. We barely had enough time to tour Shakespeare's Birthplace before we had to move on. We were not able to see the town at all. I would have preferred to have lunch on our own in Stratford before moving on, rather than going to an assigned pub.
Warwick Castle is very interesting, but is a little bit commercialized and not simply visiting an authentic castle. Sometimes it felt a little Disney. Oxford is beautiful and historic, but there isn't really a lot to see or do there. The Cotswolds portion of the trip is essentially a lovely scenic drive. This is definitely a fun and beautiful day but you will feel a bit rushed.

This was a great tour, with adequate time at each location. It's a long day with a great deal of walking, so dress comfortably and get a good rest beforehand. Our tour guide was fantastic and offered us a great deal of information about each location before we arrived. We essentially had an 'orientation' for each stop on our journey. Windsor Castle is amazing and historic. Bath is beautiful and educational. And of course Stonehenge is iconic. Definitely worth it, this was a great day.