I installed Snow Leopard (aka Mac OS X 10.6.0) on Sunday 30th August 2009 just 2 days after it was released, on my 3-year-old iMac. My iMac isn't particuarly powerful; it only has a 2 GHz Core 2 Duo processor, 2GB of RAM and a 250 GB hard drive. Snow Leopard was extremely easy to install, with few options or technical decisions to make, and took just 45 minutes to complete. I upgraded straight from Leopard and didn't have to re-format my hard drive or start over from scratch. I encountered no problems or bugs during the process and, when I got back to my Desktop, all my files and settings were completely intact.
In short, my iMac is now much faster. That's the main difference. Snow Leopard may look the same as Leopard on the surface, but "under the hood" it has been completely re-engineered and refined. From my experience, it seems like I'm running the same operating system (Leopard) but on newer, more powerful hardware. My iMac now starts up in 35 seconds and shuts down in 6 seconds. And it goes to sleep so quickly you'd think the computer had crashed! The Finder feels lighter and more fluid, with smoother scrolling and faster loading of icons. The Dashboard loads and updates more quickly, with less time spent waiting for Widgets to refresh their content from the Internet. Mail also feels lighter and more responsive, totally at ease with browsing through thousands of rich text e-mails.
Snow Leopard appears to be identical to Leopard, but it isn't. There are lots of new features and improvements to be found if you look closely enough. For example, Preview now allows you to import from a scanner, over Wi-Fi. This "just works" totally automatically, and requires no installation of third-party bloatware or complex configuration. Expose has been re-designed, presumably in response to Windows 7 copying Apple's dock (introduced in 2000), with left-click dock activation, a more organised grid layout, and the ability to minimise windows down into their parent application's icon. QuickTime Player is totally different and now allows you to record your own screen in high definition, and upload it directly to YouTube. Date & Time in System Preferences now sets your time zone automatically, by triangulating nearby Wi-Fi hotspots to determine your closest city. And one of the most useful features, automatic spelling correction is now system-wide, meaning your mistakes are corrected no matter where you type!
So is Snow Leopard worth £23.99? Absolutely, it's fantastic value at just a third of the cost of Windows 7. It makes your Mac run much faster and it fixes most of Leopard's little quirks and imperfections. I'm genuinely impressed. However, if you're not a geek, I'd advise you to wait a month or two before upgrading. Upgrading to a brand new operating system, just days after its release, is risky business and potentially counterproductive. Many third-party apps aren't yet ready for Snow Leopard, because developers weren't expecting it to come out until the end of September! So check the websites of your favourite apps for updates first, and perhaps wait for Apple to release 10.6.1 or even 10.6.2, before taking the plunge.