Scrolling with bounce is nice, but does this mean you can finally use position fixed and have it fix to the actual phone window? That's always been the real issue: you couldn't fix a toolbar to the top of the window, for example.
Position: fixed is also coming in iOS5, but it's not a perfect implementation yet. For instance, zooming does weird things to fixed elements if it's enabled, and it still covers the scrollable page area.
For my own purposes, native div scrolling is a godsend. The JS hacks were okay, but they still weren't as smooth, and worse, I had to do a lot more event juggling to handle both scrolling and the other touch controls within divs.
