It's pretty crappy (no autolocation, broken option processing, still barebones functionality). Doesn't seem actively developed, and definitely not trying to do better than redshift.
what I think is weird is with the command line tool (xflux) that once you start it, it tells you proc ID, and if you want to change the settings, you first have to kill the other process, or otherwise you get two xfluxes fighting over the colour adjustment, causing crazy disco flickering while the new one transitions.
I'd expect a tool like that to just tell the existing xflux process to change its settings.
Update: Looks like there's no new Linux version as of yet.