Thanks! That's interesting, because at work we're struggling with browser-specific regressions and were looking at headless browser testing to help solve that. I agree with all the drawbacks you listed (except #4, since some headless browser solutions let you use multiple browsers), but unit tests don't do anything to help with differences in browsers. Do you just do manual QA and hope for the best? Or is this not as big an issue for you as it is for our company? (We still have to support IE 11, so that's where the majority of browser-specific issues manifest.)
The “surface“ of my sites is usually small enough to just visual-check manually. I get that it might be necessary in some cases- note that I did say “as close to zero as possible” and not simply “zero”. My criticisms are that it is just such a Rube Goldberg-esque approach to testing something that its use should be minimized. It would be great if all browsers had to pass some standardized spec before being considered viable, that is the source of the cross-browser nondeterminism IMHO.
