While the Zune and especially the Sansa Connect have some interesting features built on WiFi (as should the Slacker portable player due later this year), neither has come close to rivaling the iPod, which (at least up until this point) has lacked an FM radio, much less a a data radio.
Through my own personal experience, I have found much improved performance through all the ICS features, especially Recent Apps where I can go back and forth among multiple apps effortlessly.
It has since come to our attention that the device may lack Wi-Fi support, which is about the dumbest move Sony could have made (especially when it is trying to push digital downloads and other online features).