The situations may be somewhat similar, I think, but the people are completely different. Tim Cook seems to be much more personally driven and quiet, focused on results and numbers whereas Ballmer comes across more as pushy and loud.
I think the problem isn't their specific styles, but rather that their styles are different from the successful founder. What happens when you have an organization that's organically grown all of its internal processes, decision-making, and even hiring/promotions to work well with a particular individual at the top and then that individual is replaced by somebody with a completely different style?
Hmm, Ballmer's particular style seems to be less conducive to cooperation and than Cook's, so I feel like Cook would still work well with the team at Apple like he has in the past, but I could be wrong!
I am curious as to what Steve Ballmer is bringing to the table at Microsoft. Somebody should do an article on him to explain what impact he has on the organization.
Based on what is written about Tim Cook in recent article it doesn't sound like Cook and Ballmer have anything in common apart from being in close range of the more famous founders (Bill and SteveJ).
This article (http://www.nytimes.com/2011/01/24/technology/24cook.html?pag...) especially paints Tim Cook in a much kinder, more professional light than I've ever seen Ballmer in!