Great addition to the franchise.

User Rating: 8.5 | ArmA II: Operation Arrowhead PC
What can I say
This game is much much better optimized than Arma 2 or even Arma 1 for the matter.
With my powerful rig,
i7 930 - 3.5 Ghz
4 GB DDR 3 - 2000 Mhz
GTX 480
; I was still only able to get 20-25 FPS playing Arma 2. Now I easily get 40-60 FPS on all high settings in Operation Arrowhead.

The graphics:
The game is beautiful. Its good to see that they finally optimized the engine. I know some may complain about the "bland" look of the engine, but hey, that what the world looks like, I think this engine truly displays "reality" so to speak better than all the other engines (the Crytek engine is a bit cartoonish for my taste). This is a simulation after all, let's not let COD boys downplay this game and compare it to 2009's biggest run and shoot scam in video game history.
Whats great about the graphics, especially the visibility option, is that even if you set your visibility to low, 1-2 Kilometers, you'd still be able to see the beautiful landscape in the far background, unlike in Arma 2, where the far-stretched landscape disappeared as soon as you lowered your visibility. Here, you'll be able to enjoy the far horizons, hills and mountains - really makes you feel like you're in mid-Asia mountain valley.
They've also added the hot-air effect now, a sort of desert mirage sort of wavy screen.

This game is for PATIENT And MATURE players only, and I rejoice at the fact that it's a PC exclusive.

So anyway. The story is decent enough. Typical American liberation of some CIA installed dictatorship in Mid-Asia I guess. What's weird is that if you play on "Regular" some enemies (i.e. Fundamentalist Muslims) surrender easily. Now here, you can actually kill these POW's without any repercussions. However, killing civilians is a no-no. You get to make big game-altering choices just like in the first two games. It's interesting to see hostiles using old Soviet weaponry and vehicles. You could also encounter some old destroyed weaponry in the countryside, probably from previous conflicts.

The game play.
It's pretty much the same game play as in the first two Arma's. You can roll over now while in prone position. Also, there's a sort of notoriety meter. Its there to ensure that you don't impose your overt American imperialistic aggression on the indigenous population and their property. There's the usual slight general cumbersomeness in moving about, just like in real life, I guess. What's also great is that you aren't tied down to your squad again. I mean it was fun to run around with your buddies in the first two games and kick some a$$. But we know that if one of them died then it was mission over. This time, you are much more free to run around and approach your targets from any direction. In Arma 2 I liked the fact that you played as a black man. In Operation Arrowhead you play as Ben Herrera - probly a Hispanic. So Bohemia Interactive is pretty liberal and reformative I'd have to say. Also, the overall terrain is much more maneuver friendly. But it's not like I didn't enjoy running around the 400 square km of forest in Arma 2.

The bad:
There are still bugs there and there. The enemies disappear and then appear behind your back. The shot up glass windows are really messed up, how could the mess that up? Sometimes, it takes the engine a few seconds to render vehicles correctly. For instance, the wheels are squared before they turn round. Sometimes it takes an extra second for enemies to die after the grenade blast. Also, I'd really like it if the overall physics was improved. Some textures are messed up. Like you can just walk into big rocks and stay inside them.

On a personal note, it's a shame that games like these are going to be completely overshadowed by just another COD-type Medal of Honor 2010, which is set in the same environment. From the videos and the beta version, you can already see that it's just like COD and Battlefield 2 put together, what has the medal of honor series turned into? but perhaps it's too early to judge.

Anyways, it's good to know that there are still good games out there that aren't marred and watered down for the consoles.