Oh we love it when Ballmer gets feisty, even if his company is the underdog at the moment.
At a UK Tech Days event today, Ballmer gave his spiel about Windows Phone 7 and made some remarks about his competitors, specifically Google. He brought up the whole fragmentation issue, which is sort of a thorn in the side for developers. In short, when an update for Android is made, not every phone gets it, nor does the phones that do get it, get the same version due to OEM customization. When this happens, developers have to update their apps for specific phones to get them working.
Ballmer promised this not to be the case with WP7: "Unlike Google, if you write an app for Windows Phone 7, it will work on all Windows phones" which yeah, is a good selling point to developers. Also, with some humility, on Windows Mobile Baller noted that "We got ourselves in to a little bit of a pickle with phones, but now we're on track".
Lets hope so, as Google is playing for keeps.