Where are you reading that?!?! That no one has (yet) found any significant differences from .576, sure. But I doubt RIM is putting out new releases identical to older ones, I really do.
And if we wait a few days or a week for the early adopters, I bet some differences, even if small, will be discussed here.
For the time being, I downloaded it while its available, and now will watch this thread to hear about the experiences of those who install it (thanks in advance to those!)