As usual Ballmer is half right and half wrong.
IBM is spot on when it comes to making its OS a usable OS and a reasonably friendly OS. Sure there are some arcane things about some of IBM's OS's. BUT... here is the big difference between the two. IBM listens to its customers extremely well, where MS doesn't even know the customer exists unless they have a 10,000 (or more) licenses,
Yes it take (sometimes) years before IBM gets it right and they do get it right, most of the time. MS on the other hands just pushes new version of its OS out faster than the market can absorb it and or pushing a bad OS onto the unsuspecting people.
As far as one thing IBM does well over and above anything MS has not even attempted to do is documentation. When is the last time you needed to know something about how the internals of a MS product work? IBM does this on a timely and reasonably straight forward manor. IBM, last time I looked had 3 or 4 DVD's packed full of just manuals alone. I have yet to see anything close to one manual out of MS. Also, IBM (with input from the users) have always documented (well I might add) just about everything in their OS (and the IBM applications). Sure they have some undocumented items and IBM does charge a good penny for documentation (I think I heard $25K for one manual) but the 99.99 percent of the other documentation is essentially free albeit it $40 (approximately) for 3 DVD's packed full of manuals for users to read and use.
Is IBM focused on corporate rather than end user, yes, but then they (for the most part) do not interact for the most part with end users. The only exception was possibly OS/2 and yes IBM blew it because they did not court end users like MS does.
One last stab at MS and they could only dream to have a OS as stable as OS/2. Typical MS it is easier to reboot than to fix the problem so it does not happen again.