Third and fourth gen Sony sensors are extremely good when it comes to pulling up shadow details. I almost never bracket anymore. But you cannot pull down highlights really, because the details are not there if highlights are blown out. So it is pretty much always preferable to underexpose when faced with more extremes of dynamic range, then pull up shadows in post.
Current sensors are also often referenced as ISO-less or ISO invariant. Jim Kasson and Bill Claff have done a lot of technical work that appears to show sensor gain increases from base until 640, then drops again (I think I said that right). Since that gain is what produces noise, this is why some recognize an advantage at 640 versus slightly lower ISO. You may want to experiment with it a little.
