3 years since purchase, 1400+ hours on record. Guess I’m experienced enough to write a review for this game.

Do I love Counter-Strike: Global Offensive? Yes, I do, and I will go on playing as long as I am able to.
But it is purely a subjective attitude. Too bad there is not a “Neutral” option for the review, and the choice hurts my @ss as badly as getting killed by a camping enemy or blinded by a teammate-thrown flashbang.
Well, it is a game anyway. Really nice and worth your bucks (Yes, it is) as a game on PC. Powerful engine (Source, been loving it since Half-Life 2), good scenery and textures, realistic physics. Nearly everything a PC game aims to show off.
But this is not the point. You will not applause for the beautiful program codes.
Something larger will get to you, or even change you.

This prettily depicted game is heavily based on online multiplayer, which means it does not have a single-player storyline. Plot, new game + and secrets will not work to raise your total time played. Instead, teaming up and battle with other players is your objective.
It is a coop competitive game, with extremely intensive PvP.
You play games for fun, but you may not find it here.
First, this game is NOT easy. As a First-Person Shooter, it requires more than seeking enemies with your crosshair. Guns here have significant recoils (relative to other FPS games), and spread patterns. You will know where to place the crosshair, AND how to control your gun so that the bullets do not launch themselves from the ground and head toward Mars. In simpler words, you need skills.
Every game has a community, and when it comes to competitive, consensus demands it to be ugly. It is not nice to newcomers, as people always want efficient teammates. While there is a matchmaking mode (Classic Competitive Mode), the rest are harsh. If you are new to it, you should try single-player with bots (AI) first to get yourself into shape. Or, you may end up being r@ped by the enemy team tactically, and by your own team verbally. Trust me, the words they use are devastating.
You may have fun with bots, but what is the point in a multiplayer game? You want to play online, and you should, but tread carefully. You need to improve your skill to a certain level to avoid mad screams of teammates. But would you expect this path of improvement to be flat? This is the barrier, the barrier blocking the CS series to the public for 15 years.

Recommend it or not? I don’t know.
I present a thumb-up for its graphics, its challenges, and reputation. Nothing more.

But for those new to it, remember:
In this game, sorrow is the predecessor, companion, and descendent of fun.