It's shipping with Android 2.3 Gingerbread, and that's pretty decent. I've used it on a number of tablets, and it's significant improvement over its predecessors. Still, I'm looking forward to Android 4.0.
I've got a 4.0 tablet on my desk at the moment. It's the Skypad Alpha 2, and it's been running a beta release for the past couple weeks. I see number of features that I like, including the taskbar long the bottom of the screen, the "recent apps" menu option, and a generally more tablet friendly interface. Fewer menus cover the entire screen, nd with ICS it's a lot easier to do bsic things like turning on the Wifi without having to leave an app. (You might snicker at that, but Android is chock full of annoying little hindrances like that.)