Elixir 1s came on my Fatty, which I got in late December. They worked well, excellent modulation and nice and quiet. They felt almost as good as my Magura Martas.
After about two months, the levers pulled to the bars, so they went to the LBS for a bleed. LBS likes Avid, and owner is very meticulous, so I'm confident that he did a very good bleed.
Another few months, and the levers pull to the bars again. So I bought a bleed kit (the Avid Pro one) and did a bleed myself, as well as shortened the hoses and changed pads. I doubt that I did as good of a job as the LBS, though. So no surprise when one of them needed another bleed a couple of months later.
When they are working well, I really like them. So not a disaster for me, but mine have needed quite a bit of attention in the form of regular bleeds. I haven't bled my Magura Martas in at least 2 years, for comparison.
IMO, Avid probably needs a little bigger fluid reservoir at the master cylinder to allow the system to deal with air a little better. So, we'll see what the future holds...