You seem like a reasonable person, but this comment goes against the experience of almost every other person with a similar setup that has ever posted about it. it seems like a bit of a troll.
You say Windows is "... by far more responsive" and has an "... instant response..." but then claim right below that, that it's some marginal mili-second timing thing. This tells me that the intent of your post was more emotional than factual and that you are probably exaggerating just to make a point.
The claim that Leopard is in fact faster than Vista is more than supported by the facts.
You read too much into that.
When I click on something and get an instant reaction, it is far more responsive.
When, I click on something in OS X, and get a response in a reasonable time-frame, it's still responsive but feels much slower.
The thing is, that everything in Windows Vista on my Mac Pro feels "instant".
Everything in OS X feels responsive, but not instant.
Essentially, it's like it is reasonable performance, but not what I would call fast.
It responds quickly. But, it definitely doesn't feel "snappy".
The speed at which Windows responds to my actions almost feels like it was anticipating what I would be doing.
In OS X, it feels more like it waited to see, and then reacted.
Naturally, neither OS knows what I want until I tell it. But, with Windows Vista, it almost feels like it already knew and was just waiting for me to tell it.
No emotional connection there at all. Just stating how different it feels when I switch back and forth.
I don't gripe about the responsiveness of OS X. I use it constantly, and I like it.
But, when I switch to Windows Vista to perform a task, it usually feels like I just stepped up to a faster computer.
With Windows Vista, I see less compelling reason to choose one OS over the other. Vista is very nice. If I didn't simply prefer OS X's method, I would see little reason to choose OS X over Vista.
With Vista, my only gripes would be related to Activation, license terms, and the way that every program has a piece of it running in the background even when not in use.
Aside from that, I find Vista to be very nice, very quick, and as stable as OS X.
I've had more issues with Leopard than I have with Vista. But, the issues I've had with Leopard have all been minor and fixed after some time in the terminal.
So, I wouldn't say anything bad about Leopard either. It had minor issues that were fixed quickly. I just hadn't had any issues with Vista.
Aside from the minor interface changes, Leopard feels just like Tiger. No faster, no slower. Just about the same.