CPU: Intel i7 4790 (Stock)
GPU: MSI GTX 970 Gaming 4G (Stock)
RAM: Kingston HyperX Beast 16GB 2133CL12
Motherboard: MSI Z87M-Gaming
Storage: Samsung 840 EVO (OS)
Storage: WD 1TB 7200RPM (Game)
Display: Dell P2415Q 4K
This is where things begin to look not so pretty. Usage of Super Sampling murders performance so badly, it's simply not worth turning it on. FXAA is most certainly good enough, and on 4K, you simply don't need AA at all unless you have ample horsepower available. This is a game built heavily on physics, and with such great floppiness comes bugs and breakables. In multiplayer particularly, it's incredibly easy to break the game in its entirety and cause your character to die and fail the mission. In some cases, the screen simply went black, requiring a total restart of the game. There were even cases where the AI for certain units didn't actually load - so on the final boss fight where there was a little machine that wheels around a molten boulder. Unfortunately, it didn't load AI, got launched into their air, and we simply couldn't kill the boss. The game is ridden with bugs and kinks all over the show. To be blunt, it still feels severely lacking in polish. It still feels like it's in Early Access.
Besides bugs, the game ran beautifully on my machine performance-wise. Only when you turn on that Super Sampling was my machine utterly murdered down to 16 FPS. I would only use SSAA if you're on a low resolution like 720 or 800 pixels high, and have a fairly capable GPU solution.
For reference, you can see how your GPU will perform in comparison to ours with this set of charts.