It all depends on how far along ATi are with mastering the .13u process, full credit to their hardware people for the R300 design. I don't believe that they will get much more out of the .15u process and they may run, or have run, into as many problems as nVidia, AMD, and Intel did with their swap overs.
My opinion is that the TSMC and other delays have meant that nVidia have had no option but to take their time. They didn't really have much choice. And now they are still not in full control of what happens. But in the end they will have the design and knowledge of the proccesses involved with this new technology to jump ahead of ATi.
I also can't see ATi releasing a better R300 after only 2.5 months of the R300's lifespan have passed. It would almost be admitting that it wasn't as good as it could have been and that they rushed it out to get the jump on nVidia.
Folding for Beyond3D
"A lie gets halfway around the world before the truth has a chance to get its pants on."
Sir Winston Churchill
"Halflife2 got halfway around the world before Gabe had a chance to get his pants on."