Hey Daren,
As you asked specifically about Alpha channel features, I can comment.
I just completed 86 greenscreen vfx shots in Resolve. In 4 hours. Yeah, I’m using Resolve for keying and compositing.
If I only had a few shots, I might have pre-graded in resolve, and used after effects and keylight to key. But I had 86 shots, which all needed motion tracked garbage mattes. It was actually better and faster to do the composites and keying in resolve. I built my keys with the panel, which was much faster to clean and preview. I used the motion tracker to build fast garbage mattes. I was previewing everything almost in realtime, and color graded the plates to match perfectly.
I always hoped to one day do compositing in Resolve, but never thought it would actually happen this soon.