Pro Makes you feel more for your characters than most character driven games
One of the more fun parts about this game is managing your squad. You can customize the looks, voices, and even names of your soldiers. As you take your soldiers on missions you'll get attached to them. This will create a lot of tense moments when your soldiers are about to die and you desperately try to save them.
If you decide to input the names of your friends or family, multiply the tension by ten.
Pro Excellent suspense
You're always against the clock in one way or another. Globally your enemies are moving forward with their plans and unless you actively work towards countering them, they will win. You'll be short on cash, manpower, and will have to work with inferior tech. On the field most missions have turn limits forcing you to act aggressively. This scrambling for resources, making with what you can, racing against the clock creates great suspense that makes it all the more satisfying to win an important mission.
Pro It's fun to upgrade and manage your squad
As you progress through the game you can train and promote your soldiers to make them more effective in combat, unlock new abilities and upgrade their weapons armor. The interesting part of it is if a member gets injured (which is really easy to happen on the harder difficulties) they are not available for the following missions until they heal. So if you only upgrade one solider and he/she gets injured, you're in a really tough spot.
The weapons, abilities, items and armor you can unlock are varied and interesting enough to make it really fun to progress through the game and build a custom squad based around how you like to go about your missions.
Con Steep learning curve
XCOM 2 is not just about managing a squad of soldiers, you also have to manage your base and operations on a global scale. This includes managing your resources, identifying which missions you should prioritize, and allocating research for new technologies. It might take a while to learn everything needed to fully enjoy this game, especially on higher difficulties.
Con Performance could be better
Even when using well above the recommended hardware the game does show some performance issues as it is difficult to hold 60fps. While not the biggest problem thanks to this being a turn based game it would have been nice to see better performance and a constant 60fps when using what the developers recommended for best performance.
Flagged Pros + Cons
Pro It's fun to manage your squad
One of the main aspects of XCOM 2 is preparing your squad for each mission. You need to consider the terrain, objective, and enemy types. Based on these you'll select the appropriate soldiers, weapons, and gadgets. A lot of the missions have some leeway, so you'll be able to form a squad that fits your playstyle. It can either be a group of stealthy rangers, running in with machetes to surprise the enemy. Or it can be a group sharpshooters, allowing you to systematically clear the area from afar with sniper rifles.
After each successful mission/kill your soldiers will earn experience. With enough experience you'll be able to promote them and earn learn new skills. You can also research new weapons and build them. A lot of it comes down to looting alien technology and reverse engineering it back at the base.
All these things add up and it's really exciting watching your soldiers grow into unstoppable killing machines.