I’ve been a long-time fan of the Firefox web browser, and I’ve been enjoying some of the new features that have been creeping into the beta builds lately. But I recently upgraded my Mac to Safari version 4, and I have to say, I am very impressed!

Acid3 tests a browser’s compatibility with Web 2.0 standards. When I ran this in Safari 4, I was surprised to see a result of 100/100!

My current version of Firefox, 3.5b99, made it to 93/100.

I do enjoy the usefulness of some of Safari’s new features, such as the Top Sites grid and the Developer tools. Others, like the Cover Flow view in History, offer some pleasing eye candy. The main improvement seems to be in Java-script engine performance. Gmail loaded noticeably faster and my Netflix queue drag-and-drop was much snappier with Safari 4’s “Nitro Engine.”

Both browsers offer a new “private browsing” mode, dubbed by some “porn mode.” Firefox seems to have a better implementation of this private browsing experience by suppressing cookies. Safari, on the other hand, keeps your cookies present when switching from normal to private browsing.

To test this yourself, login to Google while in normal browsing mode, then activate private browsing, then reload Google and you’ll see you’re still signed in. Try this again with Firefox 3.5b99 and you’ll notice the same doesn’t happen.

Safari’s private browsing seems silly when cookies stay intact, allowing websites to still identify the user. If anything, it gives the user a false sense of anonymity!

Private browsing flaws aside and despite the features and speed increases, until there’s an Adblock Plus for Safari, I’ll probably stick with Firefox as my primary browser. I’m sure others have extensions they’re attached to as well, and this alone may keep market share with Firefox.