I switched to these from Martin Lifespans. Lifespans are good strings as well, but for me there's just no reason to go back. The guitar (Martin DC-16RGTE) sounds smoother and more balanced with the Elixirs, although I can see why a more traditionalistic player might prefer the clangier, less "hi-fi" sound the Lifespans gave it. But the feel is unarguably from another planet. So smooth they actually made the guitar easier to play. The Elixirs are also a lot more durable than I imagined, and I spend less money on strings for the Martin than ever.
I also got to compare these to one other brand's coated acoustic strings, when the g-string tuner of my Ibanez had developed a sharp edge and cut the string and there wasn't an Elixir spare around. The newer Curt Mangan g-string went bad while the month or two older Elixirs were nowhere near their end...
I'm very satisfied with these strings.