Conclusions
We've learned a couple of things from this little exercise: stereo 3D has come a long way since the early days of 3D Vision, and it still has a way to go.

Inconsistent game compatibility is still a potential issue. In our experience, Nvidia is far and away the winner on that front, but judging by the frame time spikes we measured and the need to tweak settings in Deus Ex, even the best solution on the market isn't perfect. AMD, meanwhile, suffers from a fragmented hardware ecosystem and patchy support for even major titles. Battlefield 3 still has visual bugs with the latest driver release, and Arkham City lacks proper support of any kind right now. More worryingly, we encountered a rendering bug in Portal 2, a game that's been out for over nine months and really ought to work without issues at this point.

Another problem lies with the displays and their matching active-shutter glasses. The vast majority of 3D monitors are based on TN panels, which have improved in recent years but still exhibit clearly inferior color reproduction and viewing angles compared to IPS offerings. TN panels have quicker response times, a vital quality for active-shutter 3D configs. However, our testing shows that even Asus' VG278H monitor, a $700 solution with lightning-quick response times, still produces bothersome ghosting in certain games—and it's the display Nvidia sends to reviewers. That makes the prospect of slower IPS panels coupled with active-shutter goggles seem unworkable, at least for now.

On top of that, the rapid flickering of active-shutter glasses can cause eye fatigue. One day, after testing, I went to the theater to see Tintin in 3D. I was amazed at how much more comfortable the stereoscopic visuals were, simply because the RealD polarizing glasses didn't flicker. Even with wide game compatibility, no ghosting, and perfect color reproduction and viewing angles, any stereo 3D setup that relies on active-shutter glasses will be flawed to some degree.

The price and performance issues are worth noting, too. A stereo 3D config requires considerable graphics horsepower. Based on our performance results, a $300+ card seems de rigueur for stereoscopic gaming at 1080p. Add the price of a sufficiently big and bright 120Hz panel with the latest glasses, and you could be looking at a thousand-dollar expense. That's a lot of money to spend on a capability that doesn't improve every game substantially, a capability that forces one to trade visual fidelity (in the sense of graphical bells and whistles) for the illusion of depth.

Help is on the way, at least for some of the problems we encountered.

AMD says Microsoft will include native stereo 3D support in DirectX 11.1, which will ship with Windows 8, in the form of a new quad-buffer API. (Incidentally, that API will be incompatible with AMD's own quad-buffer API.) We don't know yet if DX11.1 will be back-ported to Windows 7, but in time, game developers should be able to support both Nvidia and AMD stereoscopic setups through the same API calls. That doesn't mean they will, especially considering the abundance of shoddy console ports on the market today. If devs do take advantage of DX11.1's quad-buffer API, the stereo 3D experience should be more consistent across different configurations.

All things being equal, I would undoubtedly prefer stereo 3D over a lack of it—but things are not equal. Not anywhere close.

In other news, AMD told us about an IPS-based 3D monitor due out this quarter. The display uses line interleaving coupled with passive, polarizing glasses—a design that should offer greater color fidelity without the troublesome flickering associated with active-shutter goggles. AMD says the polarization constrains vertical viewing angles in stereo mode, but horizontal viewing angles are purportedly "outstanding." Our limited experience with line interleaving makes us wary of other potential tradeoffs, though.

All of this raises one simple question: if you can afford to, should you hop on the stereo 3D bandwagon now?

Personally, I think the negatives still outweigh the positives. On one hand, you've got the high cost of entry, flickering, ghosting, a huge performance hit, and compatibility kinks (on the HD3D side). On the other, you've got... what? A fleeting "wow" factor that's there in some games and absent in others? It's true PC gaming is all about enhancing the experience in subtle ways, but I think stereo 3D requires users to jump through too many hoops for too few enhancements. All things being equal, I would undoubtedly prefer stereo 3D over a lack of it—but things are not equal. Not anywhere close.

If you're feeling the itch and can afford a good 3D setup, I won't try to stop you. You'll certainly enjoy the experience in a few games, and depending on your point of view, that might make the investment worthwhile. I will, however, suggest that you favor 3D Vision 2 until HD3D's patchy game compatibility is, er, less patchy. There's really no sense in going through all the trouble of building a stereo gaming rig only to encounter compatibility problems in every other game. Also, whatever you do, don't skimp on the display; it can make or break the experience.