I wouldn’t like the IBM situation at all. I don’t mind putting in my 40 hours, but anything over that makes me grumpy.
I am heavily addicted to the 40 hour work week, and I’ll do some serious grinding to keep it to that. Which of course irritates the hell out of my “showoff OT” coworkers as I go home before them and ahead of schedule while they’re behind. But that’s OK, I don’t respect them anyway.