CPO is still better on average than non-CPO.
If our Audi had been CPO, the extended warranty would have saved me big bucks. It is less expensive to make CPO used BMW payments than it was to keep the A4 perfect with no car payments.
With the Audi we figured we were good - low miles, owned by my brother, well maintained by the dealer with records (pages of them). By the 30k mark the entire interior had been replaced under warranty so it was like new. The tranny was done under warranty at 12k. The stereo system shortly after. But man, when the warranty ran out, all bets were off. Coils, diversion valves, the whole PCV system disintegrated - twice, the alternator pulley went out, the dipstick broke, the dipstick tube broke, the hood release broke, oil leaked out faster than it could be refilled. Inner cv joints went on both sides requiring dual axle replacement - best guess is that they were mishandled when the tranny was pulled - no warranty for that. Random icons on the dashboard about dipper lights that weren't out. Rear cam chain tensioner went bad, etc, etc, etc. I think the car would have imploded before 70k (and yet I have a friend with an identical car that has been trouble free!) which just makes the sting that much worse.
It was quite a shock coming from a line of maximas that never needed anything other than an occasional coil pack.
Now we will not buy a used car without a CPO program, even if their inspection is lame, your are still covered - you might just have to fight for it.
Our CPO BMW had a few items missed on their list, but we got them to address them. On their list it actually said , "car pulls to left". When we picked it up it still pulled to left.