High quality models, amazing animations, great map.
It's a super useful DLC for a specific group of people - cold war nerds and milsim players.
It's what made me come back to arma, as it offers something new but with the same or even higher quality than what BI provides. The only ♥♥♥ would be the campaign - it's rather bland. Other than that, worth the money.

After spending a whole lot more time on it, I thought I'd give this review a more in-depth explenation:

The CO-OP missions included with GM are a lot of fun. Having played them many times with various members of the community and Team 13, there isn’t anything bad to say about them - they’re simple yet interesting, and a blast to play with friends. It’s something I wish we had more of in vanilla arma 3, simple fun, because hardly anything beats defending a crippled town as West Germans hurl towards you.

The asset quality in GM is insane: it’s something never seen before in Arma on this scale, as even some of the vanilla vehicles and rifles look out-dated compared to what is present in the DLC. The vehicles are fun to use and realistic, the models are exceptionally well done, and the variety of them is large; every one of the four factions is unique, seeing as every nation gets different variations of weaponry. This means that the Danish differ from the West Germans, and that the Poles also get different equipment as compared to the East Germans. I won’t delve deeper into that, but I recommend taking a look at what composes these factions yourself.

I wouldn’t be able to mention GM without mentioning it’s community - the DLC’s discord is filled with enthusiasts of both Arma and the Cold War, the communication between the players and the developers is outstanding, and when one of the devs, Mondkalb, created a casual Arma 3 server for the community to play on, Team 13 formed. Although I may not play with them every time anymore, I’m forever thankful for that. What also needs mentioning, is the modding community: with the addition of samples retexturing has become significantly easier for anyone wanting to make modifications with the DLC. Not only that, but Vertexmacht provided multiple GM Extras on the Steam Workshop to be analyzed, so that modding could be easier. Alongside that, new variations of existing equipment also made it into the game to encourage modders and the community even more.

Ever since it’s release, GM has seen multiple free updates and bugfixes. 1.1 added the Polish faction, new vehicles, equipment, and 90’s Denmark, 1.2 added special forces units, again new gear and equipment, and unique helicopters and short take off and landing aircraft which we’ve never before seen in Arma. Not only that, but another update is on it’s way and currently in the Developer branch; it adds 90’s West Germany, the legendary Marder and UAZ’s, and a ton of other new stuff.
The support that this DLC has received from it’s two developers is insane - these updates keep the community alive and hyped to explore the cold war, expand on the existing assets, and they’re free.