42 Pages of unhappy customers means at some point in Apple's Marketing campaign they failed to adequately inform customers of the limitations of the hardware they sold, and implied to a large user base that Mountain Lion + Apple TV equalled the ability to 'Air mirror' their desktops.
Apple's policy is also to shrowd their product releases with a veil of secrecy. The specifications you are talking about are often not revealed in advance of product launches.
Many of the people complaining have purchased Apple TVs on the basis of this sales campaign.
I have no issue with a twenty dollar upgrade for an OS. I happily did not bother to pursue a free upgrade to Mountain Lion from Snow Leopard that I was entitled to because I understood that a major upgrade would have a certain number of bugs, and I was happy with snow leopard, but I am NOT a happy owner of two apple tv's purchased and shipped to me a month ago so I would be able to use the mirroring functions advertised, and a mac mini purchased in July of 2011, that does not appear anywhere on receipts, or identified anywhere as a 2010 model.
I would probably have been happy to purchase a new Mac Mini instead of the AppleTv's I spent my money on if Apple had spent more time explaining the differences between their new hardware's processing ability compared to their older models, and had given Intel credit for the new functions their OS was able to offer.
Air Mirroring is a feature dependant on their more recent hardware and should have been marketed that way, rather than as a feature of an OS that is software related.
I am also less than impressed that my brother in law who has 6 '2009' MAC Pros cannot purchase memory upgrades from Apple and that trying to identify his hardware using the MAC Info function in OS/X does not list a model year, if that is the terminology that Apple is going to use for marketing purposes.
I have purchased Airparrot, and I am forced to agree with Apple that the Mac mini I own is underpowered for air mirroring. I would be very surprised if my brother-in-laws MAC pros, with 16Gb would be unable to perform the software encoding necessary.
I have purchased:
1 Macbook 2007 model, 1 Macbook Pro 2009, 1 Mac Mini 2010?, 2 Iphone 4s, 1 Iphone3gs, 2 Apple TV's.
My brother-in-law has easily spent in excess of $20,000 on Apple equipment for his Graphic design company.
As a result of Apple's poor marketing and poor product support, two previously very happy customers are left with the impression that Apple does not accurately advertise their products.
I will be skipping several upgrade cycles to be sure that Apple's hardware has caught up to their hype.
I am also glad I didn't send my brother who is a university student an Apple TV as a birthday present as his $2000 Imac I tried to discourage him from buying two years ago, would be underpowered for presentation purposes.
A lot of people who have trusted Apple to sell hardware that wasn't easily upgradeable are questioning what they were thinking when they bought a computer with no expansion ports,and non-exchangeable CPUs. I know the Apple Macbook Pro with the Retina display is looking distinctly unappealing to me now.