Tim, thanks for your comments on Portra 160 vs. Portra 400.
Here are two samples that irritated me, based on that I would never choose Portra 400 but it seems to be a function of the Howtek (mine doesn't work properly, I cannot compare it myself) - especially the "sparkling" noise in the shadows:
It's extreme compared to my sample of Ektar vs. Portra 400
Many tests have been seriously flawed and irritated many photographers I know - a <800ppi-drum-scan of 8x10 is soft, a 11MP-Canon beats a 6x7-slide. Yes, it's still the old "film vs. digital"-debate and it's tiring - but I don't see the point of letting faulty tests dominating the internet.