On our Northern Tier trip this summer, we caught up with the AC tour. It appeared to be a well run tour with a good leader, and a compatable group.
Frankly, other than fellowship, I don't see the need to tour with a group. The group appeared to be tied into a schedule and exclusively campgrounds. We usually didn't decide on a nightly destination until after lunch. And, depending on where we were and the weather, it was either a motel(20%)or a campground (80%). We liked our flexibility.
Also, the AC costs more. I figure we spend roughly $2700 for two of us for 56 days. The AC tour cost roughly $3300 for 90 days.
Now, depending on your goals, a group tour might be nice. I could enjoy a week or two of companionship and fellowship along with a more leasurly pace. The New England excursion has peaked my interest, as has many of the cross state tours offered by in many states.