Alright so I've been playing the came (a lot) and I have mixed feelings so far.
Pubs are great and I have a blast grinding them. The supply drops make the game so much more fun. Nothing better than getting a bad ass Elite helmet after a game. So far Uplink is my favorite gamemode to play in pubs (though SnD gives you the most XP in general).
I've been playing a lot of competitive, and at the beginning, it was a bit shaky. Hardpoint was really hectic with how fast the game is with the exo suits and the map size. Due to how fast you can get to one place from another, people are kind of all over the map and it messes the spawns up quite a bit. People started putting a 2.5 second respawn-timer on to help the spawns adjust to the exo suits, and that helped quite a bit. The new hardpoint with the respawn-timer is a lot like Bo2 Hardpoint, which was (arguably) the best gamemode in competitive CoD history.
On GB, the rules are all kinds of fucked up so I won't even talk about that. But on UMG they seem to be getting a hang of it. They have the SnD map rotation down to 5 maps (compared to 8 maps on GB), and have banned the "Cloak" and "Stim" exo abilities.
The third mode has still not been decided. They're deciding between Uplink (what the creators of the game really want as a competitive mode), and CTF (what all of the Pro players, and most of the community want). They've been trying to tweak uplink so it's better, but the game has only been out for a week, so time will tell. The main problem with the gamemode is that you can throw the ball literally all the way across the map to your teammate (there's a button you can press if you're looking toward a teammate, and the ball literally hovers to them at a very fast speed and can go any amount of distance). This causes people to just camp the ball respawn, throw the ball right when it spawns to their teammate that is camping the enemy's portal and score over and over again. I think if they get rid of the passing mechanism entirely (you'd have to toss the ball like you would toss it into the portal, which is not a very far throw), they could probably make it pretty competitve. Also think there should be a 2.5 second respawn timer and possibly make the ball respawn at 3 different points (at random) on the map instead of the same one every time. This would require teams to spread across the map, instead of all of your teammates in the same spot camping the ball respawn point.
The game's only been out for a week, but I feel we have a great year of CoD ahead of us. In both the competitive and casual scenes.