It maybe just me but I'd take a second hand ebay 2008 Mac Pro for $2500 over a 2010 home-build PC running any version of Windows. The 2008 3.2 Octad is can still kick the ass of most of the 2009 Mac Pro's so all this obsessing about 'this years must have' is really relative to your budget.
The 2008 MP's offer a good value to those that have them (and bought new or refurbished; used, maybe, maybe not, as some are priced rather high).
But that's not what my post was about. Rather that users that have extensive software investments under OS X are limited to a single system vendor (as it's pros, hackintosh's aren't typically an acceptable alternative given the potential support issues = user is on their own).
Generally speaking, I see computers + software as tools. If one solution is better for the usage, then that's the better choice. So for some, OS X is the better solution, others, with falls under a different OS (PC's can offer more choices in terms of finding hardware, but the software may only offer about the same number of limited choices as are available under OS X for professional use).
Some users may have realized that their usage would be better served by switching to another OS for the available applications suites. But because of the existing software investment, they're "locked down" to what they're in due to budget restrictions. And this can apply to whatever OS/applications are being used.
A 2.8GHz quad core Xeon Workstation from Dell starts at $1037 with a 3 year next business day warranty. If we try and make equal comparisons then a 2.8GHz quad, with 3GB of RAM, 500GB hard drive, comparable graphics card, optical drive, firewire and 3 year warranty is $1,468 (cheaper with 3rd party upgrades) compared to a Mac Pro with Apple care costing $2,748.
These are the price differences people tend to focus on. $1,000+ difference for generally less hardware performance and options is a lot to pay for OS X for a good many people it seems. The dual socket comparisons are closer, but other companies lower prices gradually over the life of the product; a Dell T5500 like the base 8 core was $1,000 less than Apple before they updated. Apple also going from offering systems for processor price + $1100-$1200 to processor price + $2,200/$2,500 made a lot of people question the value of the Mac Pro.
This is where the complaint is valid IMO as well. The value once provided by MP's has disappeared with the 2009 systems.
It makes being locked into MP's as a result of OS X based software investments harder to swallow, and seems to leave users with a feeling of being taken advantage of/ripped off. This impression may be even stronger if the individual/company has lost regard/confidence for their software as well. Such as features available in other OS variants not provided in the OS X version in what they think is a reasonable period of time (i.e. available in one version for more than a year, when a new OS X version ships and it's still missing).
Perception plays a big role IMO as to how people determine their system value (including software), and Apple's hurting their own cause IMO by keeping users in the dark (not just for planning purposes for things like MTBR).