I've played a little with it. They've made some long overdue improvements like being able to quickly toggle WiFi, Bluetooth, etc. I'm not a can of the notification bar. I think they outthought themselves a little. For starters having to pull twice to get it at times? That's weird. Second is the separation. I think it's a good idea but implemented poorly. Like you can only get the weather on Today. Shouldn't be that way. Also weather is overly complex. Instead of having a picture of a sun/clouds/rain whatever it reads it like it's the weather channel. Kinda cool to know info but 90% of the time you just want to see what the temp outside is.
I also have to say I'm not a fan of their newly redesigned app appearances. I think gamecenter is comical, Stocks looks more like a heart monitor. I liked their old apps, but I can understand they may have felt they needed to not just change the OS look and leave the look of the icons the same. So I won't harp on that too much.
Overall I think it's a step in the right direction. Apple is finally stepping up to the plate to do battle with Android by offering a more 2010s experience. Will be interested in seeing Kit Kat now and what google has in store. Jelly Bean didn't bring too much new (aside from Google now and the improved voice which do rock) aside from making Android super fast. Rumors circulating around that bad boy is that it may be used to create even lower cost devices and help bridge the gap in getting everyone to Android 4+ Of course the carriers and the manufacturers still create a problem with that.