His writing is a bit whiny-ish, but he does make a few valid points.
seriously, i can't understand all the people who complain about leopard.
Well, as someone who's had a few Leopard problems, let me explain it to you

:
it's snappier than tiger,
Not for me (not yet anyways). An SR MBP with 2GB should be smoking the pants off of Leopard. Yet, I've noticed slowdowns in Office, iPhoto, Safari, and several other apps. The only app I've noticed speed up is Dashboard, which now loads about twice as fast as before. Other than that, some parts of Leopard have been down right dissapointing in terms of speed.
Funny...I never had one kernal panic or random app abort with Tiger. Under Leopard, I've had a kernal panic, several random app aborts, and other random glitches (Coconut Battery no longer wishes to show the correct number of cycles).
and only the little feature called quicklook alone is worth upgrading.
$130 for one feature? I think that's a bit extreme. I do like Quicklook, but Leopard is the sum of its parts, and with Time Machine, Spaces, Quicklook, and the other little goodies together, I'd say that Leopard was worth it (after we subract Stacks, because that feature is still not ready

).
I don't think anyone really expects it to be perfect, but from my own comparison, Leopard has been further from "perfect" than Tiger was/is.
but i think it's better than tiger (and since tiger is better than vista it's self-explanatory)
I don't have enough experience with Vista, so I can't say whether or not Leopard is better than it. However, I'm not sure if I'm ready to say that Leopard is better than Tiger
YET. Maybe after .2 or .3, Leopard will finally become better than Tiger; until that day, I'm only marginally happy with Leopard (compared to how Tiger worked out).