Hey @Gewitty,
Ansel is more thought as a replacement for Shotwell. I was just growing tired of all the crashing and the general slowness.
Considering Digikam I never really bothered to really try it. Maybe the UI is a bit confusing or it simply takes time to understand it.
The things I am really interested into, and that Ansel currently supports are versioning and diff view.
Another feature to come is collection (like in Lightroom), but I haven’t worked on it yet.
So both Shotwell & Lightroom are a source of inspiration.
But then honestly, the best way to make yourself an opinion is to try it.
For @asp and @davidvj, I have started working on the XMP tag import using exiv2