If you are using macOS, Webkit is the most obvious choice because of superior rendering performance, memory usage and energy usage. Chrome/Blink and Firefox/Gecko are not even close (and probably will never be as WebKit is as 'native' on macOS as it can get).
But lack of openness and advanced browser features on Apple's side made me embark on a project to fork WebKit and build WebExtensions API support on top of it (so you can run all Chrome/Firefox extensions on it and get the best of both worlds). We are about half-way through with API coverage. Focusing on macOS first and we have popular extensions like uBlock or Grammarly running already. We also have an iOS prototype running some FF/Chrome extensions.