
First, let me say that I tried the A2 / OA campaigns and wasn't very impressed. Eagle Wing was the shiznit, but that was the only bright spot to Combined Ops. A2's campaign just wasn't that engaging to me, and OA was too Iraq '91 / Curbstomp to be all that enjoyable. I booted A3's campaign with no expectations, just a desire to see what the story held.
By the start of Mission #2, I was blown away. Like Adams. But in a good way. Unlike Adams.
Seriously, the pacing, the engagements, the presentation of the story... spot on and beautiful. Enough of your objectives are scrubbed that you learn not to put full faith in the briefings, but enough are completed to keep you on your toes. The betrayal is timed for you to be at that great vantage point, and it's great hearing all of Stratis go to absolute shit over the radio. The missions play long enough to explore their premise a fair bit, but not long enough to overstay their welcome. When you're about to tire of wandering the forested hills, the missions throw a curve at you to keep you from boredom. The arrival of the CSAT, though predictable, was still an "Oh shit" moment of dawning comprehension, especially the way the squad-lead voice-actors sold it.
There's that wonderful sense of continuity that only ArmA can really afford. Knowing that Stratis is going to shit around you because as far as you can see, there's just pillars of smoke rising from every NATO encampment. Getting to the final objective of "Crossing Paths," and hearing on the radio that Maxwell's being attacked. But you don't really need to hear on the radio, because you can just look back over the ground you've traversed and you see it being arty'd to shit. The amount of work that went into "showing, not telling" must've been enormous.
Were there problems? Yes. The ridiculous spread on the arty in "Radio Silence" for one. I mean, holy smokes, is Charlie's mortar tube really in that bad of shape that it can't land a single round anywhere near its target? A2's laser-beam accurate shells are silly too, but silly in a non-infuriating way. Every now and then, the AI would derp and Adams in particular would prove his invincibility by walking right up to an AAF, soaking a magazine of bullets, and then jamming his rifle into the confused mook's face.
Still though. It's a brilliant campaign. The constant tension, the ever-present feeling that AAF forces could be just over the next rise, and that at any time, your mission parameters may change for the (much much) worse. Like you're almost completely helpless in the face of a massively superior force and it's all you can do to just... Survive. (see what I did there?

4.5 / 5 stars from me. Docked .5 for the artillery - too inaccurate in "Radio Silence," just slightly too accurate in "Tipping Point."
~ Ferrard