"Top rated" is usually a subjective term. "Top rated" by whom? Apple? Mozilla? M$? Magazine editors? Which magazines?
I agree that Safari is probably the closest to being standards compliant. Unfortunately that means little if the majority of sites don't even know there
are standards.
I think the reason so many use FF is because of the controls it provides for protecting your screen from ads, javascript, Flash, Java, and other stuff, while at the same time offering hundreds of Add-Ons that enable so much other stuff. It may actually have more programmers working on it than MS
or Apple has on their own browsers. That can be a blessing or a curse depending on how well they work togather, of course.
The great thing is that there is now so many browsers to choose from
for the Mac!
Use any or all of them as you wish. But remember to store your bookmarks
outside any browser so you can always access them even if you dump a browser.
Finally, no browser is perfect for eveyone. But there should be one that every one can like.