Overall the trip was enjoyable and provided an opportunity to visit 3 different areas within the Loire Valley from Paris - something difficult to do without spending a night or two in the area. However, there were some very frustrating elements of the trip that caused me to only give 3 stars - please be sure to understand these before booking this trip.
Our biggest issue was the multiple language tour - ours had 3 different ones. One tour guide translated two languages and 1 did the other. This caused us to have to often hear the exact same details in 3 different languages - really a waste of time and annoying. Our English "speaking" guide spoke very poor english and was bordering on not being understandable at all. The audio devices were constantly a problem due to their not functioning. And finally too much was crammed into one day - I know I know, I scheduled a 13 hr tour. But due to other individuals on the tour getting back to the bus late repeatedly we had very little time at the last spot, barely getting inside before it closed.

Just be aware of the multiple languages, rushed itinerary and long day. We did get great pictures though.

The only benefit of this tour (besides some occasional facts/stories) is the ability to skip the line. We bought it only for this reason and were pleased with the very minimal waiting time.
We were lucky to go on a clear day (first in a while in Paris at that time) and got great pictures.