I think Satya comes from a dramatically different cultural and professional background than Ballmer and has a correspondingly different set of priorities and ideas.
The difference is like night and day. Ballmer was all about monopolization, vendor lock-in, ruling the developer community with an iron fist, and funneling all business into the proven profit centers. Nadella understands the value of interoperability, evangelizing your own tech while trying to advance community efforts, embracing open source, and developing new lines of business independent of legacy products.
Also, Satya doesn't act like a clown in public (Developers, developers) or drops unqualified statements about products from the competition (Ballmer about the iPhone).
The difference is like night and day. Ballmer was all about monopolization, vendor lock-in, ruling the developer community with an iron fist, and funneling all business into the proven profit centers. Nadella understands the value of interoperability, evangelizing your own tech while trying to advance community efforts, embracing open source, and developing new lines of business independent of legacy products.