Technical issues abound
I played through all three missions with another reviewer online, which made them about ten times as fun. But it also highlighted the fact that even months after the game's release it's still plagued by rampant technical issues.
My partner was consistently kicked at the beginning of every mission, so I had to get to the first checkpoint, quit, and then invite him back to my party and load the level up again. Only I could see or hear the mission briefings, no matter who hosted. He and I were both kicked out at various other times, and the game even froze on the loading screen indefinitely at one point.
It's frustrating to be wrestling with shit like this, especially this long after a game's release.
It's well worth the money
Regardless, "Raven Strike" is well worth the $10 you'll invest in it. The first missions is a stealthy swamp-romp with a challenging, explosive ending; the second a tactical infiltration, with a longer, also-explosive ending; the third is a series of four segmented assassinations, each with its own feel (one a snipe, one a breach, etc.).
The dynamics here are pitch-perfect, and the level designers were really on their game. Low and high points alike shine with the type of tactical challenge that makes you say things like "Target three is rounding the corner, take out four on my signal," when you're playing in co-op.
There aren't many games that make me want to dust off my headset and actually engage with other players, but Ghost Recon: Future Soldier is one of them, and "Raven Strike" fits in perfectly.