Juan, thank you for ESD. I tried it on a couple of my projects (darks, flats, and lights). It is working really well. I am thinking now that I no longer have to spend time tweaking rejection thresholds, as ESD appears to get things right automatically.
Here is an example on a 33 frame, 40 minute Ha exposure set. ESD gets very close to my trial and error optimized thresholds, a bit less aggressive which IMO is a good thing actually (ie SNR++). A couple star core differences stand out, but on investigation this is a non-issue for me.
My optimized Sigma Clipping:
ESD with default parameters: