To answer the original question, it really depends on your specific car.
I've got a collection of quite different cars and they all require a different techinque.
The Jeep won't P&G because it doesn't glide at all. It won't DFCO either because the RPMs in normal use never reach 2000rpm required for DFCO, and if they do, engine braking soon has you back in the idle fuel map.
The Fiat is petrol, turbo and has no throttle plate, it won't P&G either as acceleration burns a lot of fuel, the CD is poor and it's very light (900kg).
It wasn't until I got the MB100 that I finally was able to give P&G (Petrol with throttle plate) neutral or EOC only, but gave great results.
The latest T5 is a P&G in gear champ
In summary it seems for heavy but aerodynamic vehicles P&G is the answer, but for light weight cars or rolling sheds DWL is the answer.