As my colleague Ed Bott pointed out quite clearly, the vast majority of the new features in Apple's new operating system, Mac OS X 10.6 Snow Leopard, are hardware dependent. So unless you are buying a brand new Mac for the start of college this academic year, the chances of you having full access to all the features are somewhat restricted.
For $29 bucks you can upgrade from 10.5 to 10.6 and regardless of whether you have the hardware capabilities to run every feature, the software will still work. By that, I mean it will install without throwing a hissy-fit.
Could this be a clever marketing ploy by Apple to get people to finally upgrade their machines to the latest specifications? If you are that desperate to have 16 terabytes of RAM and multiple processors, which apparently doesn't speed things up that much, then sure - go ahead and go nuts. Otherwise the average student shouldn't care.
As far as I see it, and granted, without actually (paying and) playing with it, I see a few user interface tweaks which just refines the whole experience, a smaller storage footprint, power management for the GPU, and words added to the description of QuickTime X like "greater", "higher" and "quality". Even reading the Wikipedia page feels like I have been violated by an Apple PR official.
I don't have a Mac (but if it did this... maybe) and some would say I therefore have no right to judge. I do and I will. Just because I am not using doesn't mean that Exchange support is the best thing that's ever happened to me. Many universities don't support Exchange for their students because the cost of licences are far too expensive.
Bott describes it as a service pack, and yes - it does. I wouldn't and couldn't call it an operating system. It seems they've simply put lipstick on a pig and dressed it up like a... well, snow leopard. As far as I can see, it offers nothing to students except the joy of being able to say you are using the latest version.
It may have its failings, but I'll stick to Windows for now.