I spent most of my life living a very dry environment, (Calgary) where stings on an unplayed guitar would last a year at least. On the guitars that get played everyday I used Blue steels for over 20 years and would get about a week out of them with everyday use, but after moving to a much more humid environment (Munich) I found my strings on unplayed guitars lasting no more than a week, and only hours on guitars I play everyday, even in my humidity controlled studio.
Elixir strings sound 99% as good as normal strings (objective) in those first few moments of new strings and stay sounding that way for a long time.
I play everyday, hours a day and these strings eliminate the distraction of rusty/crusty strings.
Elixir strings feel great, I thought it was snake oil until I tried them out, but they feel awesome, not quite slippery, but much less friction than uncoated strings.
They sound great.
Like I mentioned above, in the first moments after a string change you might notice that they are a tiny bit mellower than brand new uncoated strings, but after playing them in, these actually sound brighter than uncoated strings because that stay clean and rust free.