Game is great. Here's why:
1. It's not a run-and-gun game. As a defender, you'll mostly turtle up after preparing your defenses. You won't be able to create an impenetrable fortress, so you HAVE to have a Plan B and Plan C when things don't go according to plan. As an attacker, you have to clear rooms knowing that you're walking into a death trap.
2. Quick matches. Things usually happen very swiftly. I don't see any bullet sponging action. Kills are quick, unless players are armored up, then they can absorb more bullets.
3. The dead can speak. OK, this is major cheeseballs, but your dead teammates can talk to the living teammates. The dead have access to player views (first-person) as well as any active cameras (surveillance or drones). Like I said, cheesy, but it keeps the dead players continuously invovled in the game.
4. Awesome abilities. The Operators each have a special ability or equipment. Let me tell you, there's nothing more satisfying than killing a couple of dudes with a cluster bomb - through a wall.
5. Entries and Destructibility. Attackers can enter through any window, and blow through many walls (these walls can be fortified, but then again, can be ripped through by a special Operator). This adds a level of unpredictability, uncertainty, and tension that does not exist in other games.
6. Teamwork wins almost every time. When your team communicates, plans, and works together, you WILL win. Once you find a solid team, you love them FOREVER.