Love the game. A lot of people come here to whine about it because a new balancing system has made it more challenging for expert players, and most people who love the game don't come here to review. You can no longer have the best gun in the lobby and easily kill everyone 10x over, all of them have advantages vs disadvantages. It just depends on your play style. There is Skill Based Match Making now, as opposed to people who are expert at COD not allowing novice players to move for 3 seconds at a time without getting eliminated. Cheaters and hackers are being banned left and right with the new anticheat, so that's out too. The gameplay is more individualized, and you'll be matched with similar players. Everyone is your same skill, give or take a notch. That's actually the hardest adjustment for people. They don't like playing other Kings on the mountain.
It's my favorite COD so far, and I've played them all since 2009. It's refreshed frequently, and there's something for everyone. There's cool unique operators and special weapons in the store, another thing people who don't buy them complain about. Store bundles are completely optional, just for customized fun.
If you're new to COD I recommend BO6, just give the system a few matches to pick up your gameplay and skill and match you accordingly.