When I rebuilt my MR2's engine, I followed the 'hard break in' procedure. That doesn't mean I beat on it - I just ran it higher than the 'gentle break in' procedure would prescribe. I believe I followed a process I found on the internets. Way to go.
After a week of break-in and several oil changes, I ran it at an autocross, in first gear and against the rev limiter.
The car's been fine. It's been running now for two years (and all of 8k miles) without any trouble. The last time I checked compression it was all within spec.
This is, of course, anecdotal. I'm not advocating either gentle or hard break in - I'm just relaying my experience.