There's more, but I don't want to belabor the point: it is not a Mac app, it is an app that runs on Mac OS. And I want a Mac browser.
MSIE is a good Mac app. But it crashes. And takes my whole machine with it. Some would say that makes it a REALLY good Mac app
Opera is a pretty good Mac app, but I don't know how actively they are developing the Mac version -- it's a full version behind -- and frankly, I dislike how it renders things. use.perl.org looks pretty bad in Opera, but looks fine in all my other browsers. And that's not the only site that has the problem. It's just weird-looking.
Netscape 4.x is not *very* Mac-ish, but it is Mac-ish enough. But it is also very old and crufty, and crashes quite a bit. It doesn't take my whole machine with it -- usually -- but it does crash too much. It is my fallback browser when my browser-of-the-month annoys me too much.