I almost always buy CPO cars; the dealers I use are excellent with regards to inspecting their CPO prior to sale.Reassuring to read.....
For the added comfort I will try the dealership first and eat the extra cost on the assumption they did a thorough once over and have checked in to the history and maintenance. Successful so far with my decision and vehicle choices over the last ten years.
When I worked at BMW a car could not be sold as a CPO if it had not been maintained consistent with the Condition Based Service system.