I have over 5,000 TV shows and 300 movies meticulously tagged in iTunes, and it's far and away the easiest option for me. I record shows daily in EyeTV that I list in iTunes, including my wife's cooking shows. Plex doesn't know what to do with them and omits half of the episodes. I had one 22 episode season double-list half the episodes twice and leave out the other half, and after about 45 minutes I couldn't untangle it. I've tried version 8 and version 9, using external metadata and attempting to use just my personal metadata. iTunes has simply been much easier for manual tagging, and even if someone here has a recommendation for me to snap my fingers and fix it - and I'd love to hear it if you do!, Plex still can't play my iTunes purchased content.
Snow Leopard isn't going anywhere.