I changed to Elixir strings last year, after using D'Addario's for a long time. I have a Martin D-28, built in 1974 and I play with steel fingerpicks, haven't noticed any difference in brightness but my guitar is evenly balanced between the high and low end. The biggest difference I've noticed, as many have said, is that the strings keep their liveness longer.

The only other thing is that I've had trouble buying the strings is acoustic instrument shops locally (not available or backordered for the past month). I guess I could shop via the internet, sounds like it would be cheaper, but one of my joys in life is hanging out in acoustic instrument shops, buying picks, strings, and womanhandling the guitars.