Snow Leopard: The reviews are in

Mac OS X Snow Leopard, the sixth major upgrade of Apple’s (AAPL) flagship operating system, is scheduled for release Friday, and the reviews hit the stands — and the blogs — overnight.

How many ways can you say “the important changes are under the hood”?

Read on.

Walt Mossberg. Wall Street Journal. Apple Changes Leopard’s Spots

For a company known for breakthrough products with cool features, Apple this week is doing something unusual: It is introducing a key product with very few new features that are visible to its users. This new release, the latest major version of the Macintosh operating system, looks and works almost exactly the same as its predecessor, but has been heavily re-engineered under the covers for greater speed and efficiency, and to add future-oriented core technologies.

David Pogue. New York Times. Apple’s Sleek Upgrade.

Snow Leopard truly is an optimized version of Leopard. It starts up faster (72 seconds on a MacBook Air, versus 100 seconds in Leopard). It opens programs faster (Web browser, 3 seconds; calendar, 5 seconds; iTunes, 7 seconds), and the second time you open the same program, the time is halved.

“Optimized” doesn’t just mean faster; it also means smaller. Incredibly, Snow Leopard is only half the size of its predecessor; following the speedy installation (15 minutes), you wind up with 7 gigabytes more free space on your hard drive. That, ladies and gents, is a first.

Edward C. Baig. USA Today. Many of Snow Leopard’s 100s of refinements are subtle.

Apple doesn’t need to make a vista-sized leap on Friday, when it migrates from its Mac OS X Leopard operating system to Snow Leopard.

In the nearly two years since Leopard pounced onto the scene, it has elicited a far different reaction from the Mac faithful than Windows Vista has with the PC crowd. So, while Snow Leopard brings solid technological enhancements to Mac OS X, including built-in support for Microsoft Exchange, there was no need for the kind of major overhaul Microsoft (MSFT) will unleash with Windows 7 on Oct. 22.

Andy Ihnatko. Chicago Sun Times. A speedy no brainer upgrade.

It’s like this. You’ve bought an old house and [are] settling in for months of renovation. You have goals for every month and many of them give you immediate and intense gratification. The cramped Avocado Green kitchen is now open and airy, doused in natural light, and filled with modern appliances. The rickety back porch is now a full deck, with a six-person hot tub.

Other renovation landmarks include a new roof, upgraded electrical service, and a new heating system with multiple zones. Boring. But nonetheless essential. These are the things that keep a house functional and livable, and ensure that it’ll still be a fun place to live in twenty years’ time.

That’s my overall take on Snow Leopard, aka Mac OS X 10.6.

Joshua Topolsky. Engadget. Snow Leopard review.

Underneath the customary OS X fit and finish there’s a lot of new plumbing at work here. The entire OS is now 64-bit, meaning apps can address massive amounts of RAM and other tasks go much faster. The Finder has been entirely re-written in Cocoa, which Mac fans have been clamoring for since 10.0. There’s a new version of QuickTime, which affects media playback on almost every level of the system. And on top of all that, there’s now Exchange support in Mail, iCal, and Address Book, making OS X finally play nice with corporate networks out of the box.

Brian Lam. Gizmodo. Lightened and Enlightened.

On deeper inspection, Snow Leopard’s inconspicuous aspects—performance squeezed from underused CPU multicores/GPUs and basic UI tweaks—are found to be the kind of refinement generally reserved for virtuosity. These speed optimizations are deep, reminding me of when a master martial artist puts the entirety of his weight behind a strike (while a neophyte would flails his limbs like a henchman in a Bruce Lee movie). The little UI tweaks are no different than when a great sculptor’s chisel works to remove everything non-essential during the final steps on a statue. Challenging 30 years of ever more bloated software tradition, the changes here are about becoming a more effective middleware between the media and the hardware, reducing friction while becoming more useful by, well, being lighter, less visible.

Michael DeAgonia. Computerworld. Snow Leopard opens door to a fab future.

The Finder — Mac OS X’s file manager — has been rewritten in the Cocoa development language. It still looks the same and behaves the same, but it is not the same. The new Finder supports all of the core technologies in Snow Leopard, including full 64-bit support, better live preview of files, and Grand Central Dispatch. The result is a Finder that is much more fluid with animations and much more responsive, and doesn’t become hung up if, for example, network shares inadvertently become disconnected.

Jason Snell. Macworld. Review: Snow Leopard.

System Preferences is also where you’ll see the ugliest evidence of Apple’s conversion to 64-bit applications throughout the system. If you’re using Apple’s stock preference panes only, everything will work just fine. But if you click on a third-party preference pane that hasn’t yet been upgraded to a 64-bit version, System Preferences will tell you that it has to quit and reopen itself in 32-bit mode in order to open that preference pane. While it’s nice of System Preferences to go to that trouble, it gets frustrating after you do the launch-quit-launch dance a few times.

Galen Gruman. InfoWorld. The 7 Best Features in OS X Snow Leopard.

When you travel, it’s easy to get mixed up as to when your appointments are, since your computer is still in your “home” time zone, and you have to mentally calculate the current time when looking at the calendar or clock. Sure, you can change the time zone in the Date & Time system preference, but it’s easy to forget. So Snow Leopard changes the time zone for you automatically (if you set that as the default behavior), using Wi-Fi mapping to figure out where you are — you will need to be connected to a Wi-Fi access point or router. iCal can also be set to adjust the times to the current time zone automatically, so your calendar always reflects the current times.

There’s plenty more where that came from. But for a rundown of the Snow Leopard’s refinements, you can’t do much better than Apple’s own lavishly illustrated What’s New pages.