Well I ran through a roll of Portra 400.
Very nice. The lack of grain when scanned is particularly impressive. Or, should I say, the lack of *intrusive* grain – I have no problem with grain in itself.
From a colour point of view, it's hard to say. Subjectively, looking at some Kodak 200 shots I have, the Portra seems to have a bit more depth and smoothness to it. I've no intention of of doing any 'scientific' testing mind you.
Interestingly, when I did a couple of black and white converstions, the Portra gave some fantastic tones.