Well, just because it uses FreeBSD (which is my favourite Unix (-like) environment) doesn't automatically make the PS4 just as great as the operating system it uses
I really like my PS3 but from what I've read about the PS4 so far I don't think I'll be upgrading anytime soon.
Sure, the specifications look interesting and it is of course quite obvious that the platform will provide more resources for game developers to enhance their games even further, no arguments there.
But when looking at this thing with my PS3 in mind I can't say I'm very excited about the new lock-ins they are introducing. For example; on the new environment Playstation users will now have to get a subscription (Playstation Plus; approx. E 50,- / year) before they'll be able to play multiplayer games. With the PS3 you don't need that.
And well, last time I discussed this model with a friend of mine (note; we're both casual players) he was convinced that the subscription entitled you to a lot of free game titles. Unfortunately not so much; those titles are only free during your subscription period; when the subscription ends so will your privilege of playing those games. Ergo; you don't get free games with Playstation plus, you only get a variable batch of games which you're basically renting.
I can see how this might still appeal to more veteran players, but for me it's most certainly not a good argument to get me interested because I don't see the "extra value"
Another big no no was learning that the PS4 wouldn't be able to play PS3 games. Now, this is something you could have seen coming considering that the PS3 also seems to have issues with PS2 games, but in the mean time they did provide some kind of emulator / rom kind of thing (iirc) which makes PS2 games more accessible.
Even so it strikes me as odd. If your console really is so much more powerful then why can't it emulate older stuff? Virtualisation (to mention one technique) has become quite common these days. And although I fully agree that playing games requires a lot more resources than average use, I can't help think that it should have been doable to be downwards compatible.
Better yet; any comments about it being too resource hungry would make more sense if the PS4 didn't continuously record all your game play no matter what. All 15 minutes of it. From what I've read so far there's no way to turn that off. Now; it might be a specific technique they're using for this which won't make this as resource hungry as I think it'll be, but even so.. Looks a bit weird.
And although I don't often use it any more (it was why I got my PS3 in the first place) you can no longer access other devices in your network. SO watching pictures from my PC on the Playstation will no longer be possible with the PS4.
Now, the last isn't a realistic argument since if Sony would want to move away from the "family media entertainment" options. But the thing is; they don't. They simply don't want you to have the freedom to use your own media resources / contents.
Instead they prefer that you use their own online media libraries (or associated libraries) to look at your stuff. Pictures? My guess is that you should upload those to Facebook or something and then your PS4 can also access these. Films? Just browse through Sony's own movie library. When you want to watch something there's most likely some extra costs involved, but who cares?
Which brings me to my main concern.. When I look at the next-gen consoles (both Xbox One and PS4) I see too much lockdown for my liking. We can no longer use our own media, instead they slowly, but steadily, try to persuade people to use their own online services.
In other words: trying to limit your options and make you dependant on whatever they have to provide.
And I think that could be a pretty disturbing move in the end. It starts slowly (just look at the app store on Windows 8 or the "BIOS boot protection" which can currently be turned off), but if you're not careful then that could change in an instant.