Oh, had 2 holidays in the Auvergne. Now I think it is lovely but it isn't very populated or popular. Inland and a long drive so puts off a lot of families I think. Knew one person from Clermont Ferrand and he was very surprised that I had been there and know someone else from the Auvergne and she was equally surprised that I knew the area.
The drive is probably the same as the Dordogne but people know what they are getting in the Dordogne iyswim. The Auvergne is a bit of a well kept secret I think.
Good luck if you do it, I'd go.