Thank you both for your input. I've been using these for uncooked sauce and haven't had any real complaints with them although I do notice the slight metallic aftertaste you mention, Jeff. However I always put a splash of good quality extra virgin olive oil in my sauce to deepen the flavour and balance the acidity, and I am unable to detect any off flavours once the oil is added. On the weekend I had a pizza party and bought a can of DOP tomatoes. There's no question they were better quality but were they 2.5 times as good (the difference in price)? I don't think so. I'll probably continue to use the La Regina's for when I'm just making pizza for myself, but if I'm having a gathering and want everything to be as good as possible I'll spend the extra few bucks.
Ogdred, you are right that they are vastly superior to Unico brand, and basically the same price. Have you tried Italissima brand? Not the DOP San Marzano (orange can) but the regular Italian plum (yellow can)? That is the brand I used to go for before buying the La Regina's by the case. They are around the same price I think, maybe 25 or 50 cents more. I should try them again.
Jeff, I noticed in the picture you posted that salt is not listed in the ingredients, whereas it is on the cans I have. I wonder if that contributed to you finding them flatter and having more of a pronounced metallic aftertaste.