There are quite a few new features. The most visible changes are top sites and tabs on top. They’ve incorporated an Apple TV style view of the top sites that you visit. They’re arranged in a curved matrix displaying a minimum of six pages or as many as 24. By default, it shows 12 of your favorite sites (you can change this by clicking the Edit button in the bottom left corner). Pages that have changed since you last visited them have a very visible star in the top right corner. You can rearrange the pages by dragging and dropping them, and you can pin them to a specific place so it’s always there. You can always get back to the Top Sites view by selecting Show Top Sites from the History menu or by keying Command + Shift + 1.

Tabs on top frees up some of your screen’s real estate to give more space for the window content. It does this by moving tabs from their own bar to the title bar. It doesn’t appear that you can turn off the tabs feature anymore; there is always a plus button in the top right corner of the window that you can click on to create a new tab. Another change that they’ve added is a handle on each tab you can use to re-order them, or drag them to another window, or tear them off to create their own window.

Another big change to the interface is the addition of Cover Flow to you bookmarks. I can see this coming in very handy particularly for the collection of recipes I have bookmarked. Since history is viewed from the same area as your bookmarks, you can also view your history using Cover Flow.

Also using Cover Flow is the new history search, which lets you search through all the text on any of the pages in your history. I honestly thought Safari 3 already did this, but perhaps it wasn’t able to search against the full text of pages in your history.

Less obvious visually, but something that should be noticeable when you visit sites that use a lot of scripting (such as Digg) is Apple’s new JavaScript engine which they now call the Nitro Engine. According to a variety of benchmark results that Apple published, Nitro Engine gives Safari a performance lead over Google’s Chrome which held the fastest browser crown for a short while.

I don’t particularly like Apple’s new full-page zoom mode that takes over where their old text zooming left off. Safari now scales images along with the text and as a result if you’d already right-sized your window with the green button on the top left corner of the Safari window, you’ll need to keep right-sizing it again every time you zoom in or out. I preferred the old way where only the text was increased or reduced because I rarely think to myself “that image is just too small to see.” Thankfully you can toggle between full-page and text-only zooming by selecting Zoom Text Only from the View menu.

They have improved their address and search fields with this release, though. Typing into the address field will give you some options to choose from rather than typing out the full address. Safari will give you a top hit that they say best matches your browsing history, it will also suggest pages you’ve visited recently from your history, as well as a selection of relevant pages from your bookmarks. Typing in the search field will give you some search suggestions via Google and will also give you some other search terms you’ve tried recently. Apple has also made is easier for people to… find the Find feature by placing it at the end of these suggestions. Now you can go to the bottom of these suggestions to find your search terms in the current page. That’s a pretty neat way to expose some functionality that is normally only used by people familiar with the Command + F keyboard shortcut or the Edit menu.

Safari offers suggestions when you type in the Address or Search field

They’ve included a lot of other changes “under the hood” that should result in a much improved browsing experience once Safari 4 is released and once web developers take advantage of some of the leading-edge standards that Safari supports. But, the last new feature I want to mention is that Safari now uses an iPhone Safari style progress indicator in the same position as on the iPhone (to the right of the address field) rather than filling the address field background with a blue bar as the page loads. Consistency is a good thing.

If you’re adventurous and would like to know how to tweak a few of the new things added such as turning off the search suggestions, check out Observation Point for the piece called Hidden Preferences in Safari 4 Public Beta.

Oh, and if you’re still on Windows, you might like the fact that Apple has gone with a native Windows look and feel for Safari 4. No longer will Safari for Windows have a Macintosh theme applied to it.