John Siracusa of Ars Technica has given the OS the most thorough evaluation we have ever seen.
Frankly, the 21-page review beggars belief. Siracusa goes into minute, uber-geek Unix detail about the new features of the OS.
If you're looking for a high-level evaluation, this isn't it. There are details of the meta-data indexing engine that powers the new search tool, Spotlight. The graphics compositing technology behind the new 2D Quartz Extreme engine are evaluated and dissected. The changes to the command line and Unix back-end - including a new launch process that evolves the Unix platform as a whole, and which Apple have made Open Source - all get the full run-down.
Overall, the Ars impression of Tiger is positive, with Siracusa ending on this, appropriate, note:
"Mac OS X started its life as the most ambitious consumer operating system ever produced. Apple abandoned its existing, 16-year-old code base for something entirely new. Out of the gate, Mac OS X was a technical curiosity with few applications, and a performance dog. A scant four years later, Tiger is a powerhouse that combines the best Unix has to offer with a feature-rich, user-friendly interface. The increasingly capable bundled applications are just icing on the cake. We've come a long way, baby."
Having used Tiger myself for the last 24 hours, I have to say that it's growing on me. I was a little underwhelmed at first - perhaps I'm just too well organised for awesome search power to be useful to me. However, the Dashboard has become an indispensible tool for little tasks, and the Spotlight-powered Smart Folders - folders made in email or your desktop that are defined by queries, and are thus dynamic - are now a part of my daily usage. We'll have some fuller impressions of Tiger over the coming week, but for now, check out the Siracusa article