I feel Tiger is a sound update. From my personal point of view, many of the new technologies are great on paper, but not so magnificent in practice - the Spotlight UI is lacking, and Dashboard needs better widgets. I love the idea of Automator, but it's too damn slow.
I agree with the above poster saying that Panther was a bigger update for the user. That's not to say Tiger's a poor update - it isn't - but it's not as essential as Panther was. After half an hour with Panther, I knew I couldn't go back to Jaguar; but after a week with Tiger, I could return to Panther without any trouble (though I'd miss the insane speed of Safari 2 I will admit).
10.4.1 will be well received though, as some of the little bugs are damned annoying.