portra400 has significantly finer grain, but honestly unless you are making enormous prints it doesn't make much difference IMHO. As far as I'm concerned the real advantage of the new film is in exposure latitude and shadow detail. Personally I find Ektar excessively contrasty for optical printing, but obviously it works well for lots of folks here. The Ektar colour palate does print wonderfully well however-- better than I've seen from scans.