Have both Avid Elixir 5’s and SLX brakes, the SLX were on my FS and now reside on my HT.
The Elixirs have more power and feel better to be fair, the SLX’s can feel a bit lacking in power sometimes although their not, must be the Servowave thingy.
Haven’t got anywhere near cooking either brake on long descents either, they both get hot and stinky but never loose power 😀
Fade wise they’re both on an equal level, both get noisy in the wet, pad life is better on the Shimanos so far. Avids aren’t exactly hard to bleed either unless you’re a hamfisted ijiot
Avids look better, and are pretty damn cheap at Merlin especially with VIP discount 😀