After I read an article on Engadget I got curious about Safari 4, and began searching the web for a “leaked” developer preview release for Windows. I thought “Why would Apple make a release for Windows? It’s designed to ship with Snow Leopard first.”, but I still did a Google search. 5 seconds later, I was downloading the build. 
It took me 93 minutes to download by torrent, but it was worth it. Why? Here’s why.
- Javascript: Insanely fast. – Javascript in Safari 4 Developer Preview for Windows is very, VERY fast. For example, if you know what’s Plurk, it’s a heavily-”AJAXified” web application which takes some time here and there to load stuff. In Safari 3, loading the “x new responses” and “x new Plurks” took me about 0.5 seconds. Now, in Safari 4, it takes me approximately 0.23 seconds. Fast, eh?
In addition, Plurking (same as Tweeting just in Plurk), replying and opening conversations is much faster now, in addition to the amount of time it takes to load Plurk. Loading Plurk is approximately 2 seconds in Safari 3. In Safari 4, it’s about 1.3-1.4 seconds, and rolling the timeline is faster than ever. Another example is the now-sluggish Gmail. As we all know, the “new” Gmail “2″ is very slow when loading messages, labels/folders, settings, etc.. However, with Safari 4, it’s now almost as fast as a native application. The only thing not faster in it is the initial “Loading (hidden)@gmail.com…” screen, but that’s ok. - Speed: Speedier than ever. – Safari 3 is super-fast when rendering pages. But, Safari 4 is even faster. Rendering pages, images, and loading javascript is much faster now, which makes browsing even more fun, quick and easy.
- Web applications: Browser not required. – A cool new feature is the ability to “save websites as web applications”. What does this mean? You choose an option to save, and save it as a standalone .exe file, unlike Prism which is using one .exe file to handle all. No shortcuts necessary, no need for Safari in the background, and it has several options like having a minimized menu bar and optionally showing some of the toolbar. (When you need to refresh, as SSBs1 don’t have a seen refresh feature and F5 doesn’t always work.)
- Less memory used: More for the rest. – In Safari 3, I had witnessed the RAM2 usage was at about 117MB during normal browsing. That’s a lot. Now, it’s shrunk down to 97MB, and that’s a reasonable amount for a browser with beautiful font smoothing, a great-looking small user interface and high-end speeds. So, you gain about 20MB for other applications.
The only downside I still wish would hit Safari, is extensions. But, this can be fixed with the simplicity of bookmarklets. Yes, those little links have so much power in them. One I have allows you to edit pages, out-of-the-box from within the browser, with no need for any installations. (See here and here)
I’d be wary of ’save as web application.’ I see serious potential for exploits there. And actually, if you get right down to it, you’re still running a browser when you ’save as web application,’ it uses all the same assemblies, consumes a thread, etc. It just doesn’t have all the other webkit driven functionality.
Personally though, the developer release on os x I found to have issues hanging on pages that require authentication, and crashing if I’m running on a locally served web application.
Yes, true. I still run a browser, but a minimized one. Like Prism is, but much faster with great font smoothing and sometimes better compatibility.
About the crashes: Yes, it does crash, freeze, malfunction and run into a “CFurl:302″ (or whatever it’s called, that’s how I remember it) error a lot, although that last bit also usually happens with the release version for Windows, Safari 3. About that crash with the local web app, I believe it’s because WebKit may’ve “planned” time for downloading and has seen it downloads in a matter of a few hundred milliseconds (since it’s local), which is why it can crash. (Rendering at the wrong time)
About a potential for exploits though: what do you mean? How can it be exploited?