I thought about this some more and really believe it's up to the conditions at the time you have to make the decision.
There's a hill that's relatively large and winding near me, it's easy to chuck it in neutral and you'd probably reach 90 - 100kph by the bottom of it, giving you a heap of momentum to make it up the other side. It's a fun stretch of road.
It's got road work on it now, so it's speed limited to 40 (or somewhere between that and 60 if you look at the 'others').
I thought about that stretch and concluded that engine off coasting would not be as fuel efficient as chucking it in second gear and 3000 RPM all the way down to maintain 40kph.
Why is that more fuel efficient (using fuel cut instead of engine off coasting)?
Because you'd have to restart the engine at the end of the coast
.
Pulse and Glide has it's place though, nice straights of road with PnG between 55 & 70, or similar bands, you do get the average speed, and on dual lane carriage ways, it works a treat as others may pass if they get annoyed with your speed 'band' selection (realistically, it's still close to the speed limit, so it's actually pretty good).
As I indicated above, to the conditions, identifying fuel cut situations which might work in combination with PnG is probably where perfection can be achieved.