I started that thread, and no-one answered my basic question: Do Campy cassettes loudly whirr?

The cassettes most likely don't but perhaps the freehub does.
Out on rides with my club, I've noticed that some of the bikes' freehubs tick (much) louder than mine (Shimano). Since they're dedicated roadies, and campagnolo seems to be what they (the guys in my club) prefer, it's probably true that they are louder.

No. At least not compared with Chris King, some Hugi hubs and similar ones that use the star wheel ratchet mechanism.

Sniff sniff I miss sydney. He would have seconded that.

I totally agree. I wouldn't buy the cheapest parts, but the expensive parts advantages IMO are indistinguishable to any but the most ardent riders. You can't go wrong if you stay in the middle.

>>>>Middle of the road is a good place to be, IMO. my road bike has Sora junk, and I can feel a huge difference when shifting on someones bike with tiagra/105. Althouhg admittedly DA stuff proably does work a bit better and saves some wieght but not worth the extra money. In terms of MTB I have ridden hard-tail treks with both deore/lx and xt/xtr. In pretty much all conditions, they shifted the exact same. The only real different was the weight.<<<<<

Interestingly enough, one of my older steel bikes has an 8sp SORA drivetrain on it...upgraded from the 6sp downtube stuff it came with 15 years ago and it was sydney who said there was nothing wrong with SORA if it was looked after. It was just against the OCP laws is all and who actually gives a s**t what they think anyways, right? Remeber that SORA even thought the entry level for road groups is actually quite a bit higher up the ladder than the entry level MTB stuff. Is it better than my 105 bike...nope. difference in weight and I expect it might not wear as well, but 15 years from now, what do I care if I have to upgrade again?

I've read every response to the post. It's not surprising that there wasn't a single response to the post that identified a single demonstrable difference in performance between group sets. I'm not saying there aren't differences, but let's face it, none of us knowwhat they are beyond the price difference and the bling. For example people talk about more expensive components having "crisper" shifting. This sounds like a marketing line. What is the measurement standard for "crispness" when applied to shifter / derailleur performance. Whatever the physical and material differences are between the component sets, wouldn't it be great if we really knew what they were? It's those differences that create the various ranges of consumer experiences with products. We might describe something as better, crisper, faster, shinier, or more durable, but those are only attributes we apply to how we feel about a product after we've interacted with it.

Maybe we can get a post from someone that knows what the real differences are that makes someone feel that somnething shifts crisper.

Of course my DA has crisper shifting then my Ultegra. DA=400 miles Ultegra=7500 miles. I dont think someone switching from Ultegra to DA will be any faster. Its like washing your car,well of course that makes it faster.