SO what makes the Andriod OS...
Notifications are more easily accessed, as well as updates to existing programs via a pull down menu on the top.
OS updates and upgrades are available over-the-air and do not require being plugged in and synced.
It does flow faster (swipes, loads, etc), has a faster upgrade cycle (currently, I can't speak for Win7) but its early so 1.5 to 1.6 to 2.0,2.1,2.2 is happening very fast per Google getting up to speed (I don't remember BB, Win, Apple, Palm, HP smartphones having this many iterations this fast when they were just starting)
sd card mounts right away
multitasking doesnt slow it down too much. in fact depending on what it is you can hardly feel any loss of performance.
the internet is pretty quick, regardless of your network.
notifications are always right there at the top and organized very well.
the only problem with the os is the battery life. other than that it is perfect. imo