Quality:
I've tried many other brands and these last much longer than the competition. No oxidation whatsoever out of the package, this is not always the case with other brands. However, this is not a coated string so if you have very acidic sweat you might want to look into those.
Sound:
They start out nice and bright and age into a beautifully balanced warm sound. They rarely go completely "off", the sound keeps aging nicely.
Feel:
The string tension and feel of these strings are very honest and what you'd want, some brands go out of their way to get a really slinky feeling but for the harder styles this becomes problematic on the lower strings.
I have been using Daddario for 10 years now.
Best. Strings. EVER.