By announcing SteamOS yesterday, Valve declared that PC gaming is more than desktop gaming, that Windows is not our master, and that—finally—cats can own Steam accounts. The free, Linux-based, cat-friendly operating system is designed for gaming on living room PCs, because PC gaming according to Valve isn't about WASD and DirectX—it's about openness and collaboration.

We're free to choose our hardware, our software, our mods, and soon more than ever, how we play, where we play, and whether or not Microsoft gets a cut. If SteamOS takes off, PC gaming will undergo one of its most dramatic changes ever—possibly one more significant than the introduction of the free-to-play model and crowdfunding. That's thrilling, but also scary as hell, so we've worked through our fears with a list of SteamOS pros and cons, followed by deep breaths in anticipation of tomorrow's announcement .

The Pros

It's free. If you have a living room PC, or plan to build one, you can ditch Windows for free. That feels really good to say, but the adoption rate hinges on SteamOS launching with native support for everything we want in a media and gaming center. Streaming games from a secondary PC is neat, but we'd rather run them natively on the machine we paid to put in our living room. It also needs native Netflix and Hulu apps, and all the other media services offered by the consoles.

Valve says it's got this covered, announcing that it's "working with many of the media services you know and love," and that "hundreds of great games are already running natively on SteamOS," with native "AAA titles" to be announced in the coming weeks.

It encourages competition in the console market. May the best Steam Box win! Windows isn't designed for TVs, so neither are many PCs. Now Valve is giving away a platform for games, movies, and music, challenging hardware manufacturers to make systems that are powerful, quiet, and inexpensive. It used to be Microsoft vs. Sony vs. Nintendo fighting for the top of the living room ecosystem's food chain—soon it may be Microsoft vs. Sony vs. Nintendo vs. Everyone.

It should run some games better. One of the few advantages consoles have over PCs (whether or not they always make the best of it) is an OS specifically designed for gaming. Meanwhile, we have Windows, which is clearly not designed to be an ideal gaming platform. With SteamOS, however, Valve claims it has "achieved significant performance increases in graphics processing," and is now working on "audio performance and reductions in input latency at the operating system level."

Last year, Valve posted a performance test of Left 4 Dead 2 running on Windows 7 and on Ubuntu, and the Linux build came out ahead, saying that the test "speak[s] to the underlying efficiency of the kernel and OpenGL." This isn't close to being an objective experiment—and we'll look forward to making our own evaluations—but it is encouraging.

It means more Linux games, and more couch-friendly PC games. SteamOS is as much about ditching Windows as it is putting PC gaming in the living room, so it affects even those firmly planted in their desk chairs. If SteamOS achieves the install base it needs for developers big and small embrace Linux, the Microsoft shackles may be broken forever.

The Cons

Steam Boxes may struggle to compete in price. A PC designed to run SteamOS skips over the Windows fee, but unlike a console, the manufacturer can't rely on game licensing fees to recoup costs—that money goes to Valve. Sony and Microsoft, however, can price their consoles competitively with that revenue in mind, which gives them the advantage. Valve itself could price hardware this way, but that would undercut third-party hardware manufacturers and could turn out to be anti-competitive. Unless, of course, Valve makes the unlikely move to subsidize the cost of these systems.

It could increase development costs. Major game developers aren't going to ditch Windows, the platform with the world's largest install base. If SteamOS becomes a competitive gaming platform, competitive developers will have yet another version to make, soaking up more resources.

The pessimistic angle is that this can only result in either lower quality games or more expensive games. The optimistic angle is that SteamOS will be embraced and prioritized by developers with the same enthusiasm as the consoles.

It could further fragment games and smother certain genres. If SteamOS eclipses the popularity of desktop gaming, developers will have less incentive to develop desktop games. Just as developers rushed into mobile and Facebook development, we could see a flood of controller-based Steam games that push niche and classic-style PC games into the slums.

It's a scary thought, but when we un-jerk our knees and really consider this scenario, it's a very minor concern. Crowdfunding has proven without a doubt that there's still a huge appetite for old fashioned mouse and keyboard PC games . The positive—and more likely—angle is that we'll see just greater diversity in the Steam library.

It gives Valve even more power over PC gaming. Valve isn't PC gaming. We know that, and millions of League of Legends players, World of Tanks enthusiasts, GOG.com users, modders, and more know that. But Steam is the most popular digital distribution service, and soon, it will be a platform . SteamOS may be free, but it's only as open as Valve allows. We don't know yet if we can use SteamOS to play non-Steam games, or if Valve will make exclusivity deals. We've asked, and Valve's answer will be a huge indicator of its intentions. [ Update: The announcement of Steam Machines also revealed that the SteamOS source code will be available.]

If you've got a passionate thought about SteamOS, we'd love to include it in our next issue of PC Gamer. We're always listening at letters@pcgamer.com.