My 2 cents is follow the OEM recommendations. They designed the **** thing, they know what's best. From my mechanical engineering background, even with today's modern machining methods, they are microscopic high spots in mating parts whether they are rotating or sliding parts. During break-in, these high spots will make metal-metal contact despite the hydrodynamic boundary layer of oil designed to keep the parts apart. With the high amount of metal-metal contact, high speeds and loads can cause excessive tearing of the metal that would have been smoothed out if lighter loading would have been applied during this period.
As for the higher HP, sure, by flogging the motor one will "loosen" the engine up sooner and you should see less frictional losses in the early life of the motor, hence, higher HP figures when new. But, I bet 20,000 miles later the same engine won't compare with a properly broken-in engine.
My 23,000 mile 1500 FI oil level does not budge in the sight window from oil change to oil change. I broke it in per factory RPM recommendations, never lug the motor, and change oil and filter every 2500 miles using the factory lube and filter (check the screen every other oil change). Also, prefill the filter as much as possible for a horizontal spin-on type. I have done this for 35 years for my cars and never had an oil burner.
Hmmm...maybe that was 3 cents worth??