I'm saying that things being pretty is not my primary concern when looking for development tools. It's OK if they are pretty, but that's pretty far down on the list of things I care for.
As for Safari's rendering engine, I see you claim that is "leagues ahead of everything else" on Windows. Are you talking about text-rendering? In that case I would like to comment on how it is different from all the other software on Windows. Running its own anti-aliasing it just stands out and looks weird.
If you are talking about speed, I honestly don't care. Same reason I am completely yawning over Chrome. If you are talking about CSS3 feature-set, I honestly don't care either, because using any CSS3 features while people are still using MSIE would be messing up the experience for about 50% of your visitors.
As for Safari being "one of only two browsers that fully supports HTML5"... You know that HTML5 is only a draft at this point? The spec isn't even finalized. The Acid 3 test even admits this much, saying it's testing features which may or may not end up in a official spec.
Excuse me for not caring very much for Safari, when Firefox is my main browser and does everything I need. I'll test my shit in Safari, but that's as far as I'm willing to go with exposure to craptacular Apple software on Windows.