We did a tour with Blue Marble in Provence and had a great time. First things first, it was not a high end bike tour, but I think that is what made it great. The group was like minded people who loved biking and didn't need pampering. Everyone became friends quickly and dinners were great fun. We had a great time and felt like we got great value for what we spent.
In terms of areas for improvement, tThe bikes were sturdy, though clearly heavily used. My wife had some chain maintenance issues but overall I would say they were OK. We did not use the sweep van service and carried our items in panniers. This made the hills a bit challenging as the steel bikes are pretty heavy.
I did not use the Blue Marble maps most days, but they were good when we did. Lodgings were clean and well-situated.