After switching to Linux I had trouble replacing CaptureOne, mostly because of its simplicity. Pretty much every setting has a sensible default, and making the most important changes to a photo (exposure, sharpening, noise reduction, levels, etc) can be done without being exposed to any overly-complicated UI.
For awhile, I switched rapidly between Darktable and RawTherapee, not really satisfied with either. Even after doing my best to learn the ins and outs of each, I could still make my photos look much nicer in 10mins in CaptureOne than in 30mins in Darktable/RawTherapee.
I settled on RawTherapee over DarkTable last month. It's still the case that I can't get as good results in RawTherapee as I can in CaptureOne (not because RT is not powerful, but rather because there are SO many knobs/switches/etc and it's hard to find the ones that actually do what I want).
The moral of this rant is, I'm exited to try this new version of DT, and hopefully I can finally settle on a RAW editor that only shows me the knobs that matter to me by default without making me feel like I'm playing with a 747's control panel.