I did some semi-serious work in Linux on the free version earlier this year. Performance was pretty good, and I believe that it did use the GPU.
The only big annoyance for me was the lack of a h265 codec. I had some FFMPEG shell scripts for the final exports, but it was a pain and I eventually paid for the full version, which I am very happy with considering it is a lifetime license. Some premium features like speech transcription, where you can select a video segment by simply selecting dialog from a text box, were a big time saver too.
With my last editing experience being Adobe Premiere in the early 2000s, Resolve was simply amazing.
It depends on the host OS and codec. On Windows if your OEM didn't include the H.265 license with your default installation you have to buy it for $1 from the Windows store (this is a Windows thing, not a Davinci thing). On Linux I think you have to pay for the Pro version which includes the license.
I think if you're working with DNxHD files you don't have to worry about this.
