I remember reading that book when I was a CFI and thinking, "Wow, we've learned a lot about basic aerodynamics since this was written!"
I unfortunately disagree, his dynamics were pretty spot on. Mushing gives you the steepest feasible glide slope, thus the shortest landing distance.
Disclaimer: Mushing in at stall is for 0.00001 percent of pilots in very rare situations. Don't be a retard, this isn't a save a bad approach maneuver. You perform this only when you have absolutely no other option available.
Originally Posted by hemaybedid
In contrast if you're low and have obstruction clearance the best thing to do is pitch forward to carry speed into ground effect and maximize your float to your spot.
Only if you are below best glide speed. Despite what is said about diving for ground effect it doesn't help you increase your range. This is especially true in high wing trainers like the Cessna as they get far less benefit from ground effect than their low wing Piper counterparts.
The loss of performance by increasing speed above best glide counters the slight benefits of reduced drag in ground effect. The result? A useless maneuver that, if used in a real engine out scenario and misjudge, could do more harm than good.
To the OP: He is right about mushing being better than diving. There is a key to this though, the key is he is right when speaking in terms of maximum performance. You have to weigh your skills as a pilot versus the ability to utilize the aircrafts full performance capabilities.
I would recommend reading the book Emergency Maneuver Training by Rich Stowell. He does a nice job explaining the relationship of the power required curve to a glide.