What's an alternative or even better multiplayer FPS than CS:GO?

Insurgency is pretty great

Depends on what you enjoy about MP FPS games. If you liked L4D, there's Evolve which has 4 hunters vs 1 monster which are all player controlled.

Like coop with friends? Check out Borderlands series, Team Fortress 2 man vs machine, Insurgency PvE coop , and Sniper Elite Nazi Zombie series

Like military sim shooters? Battlefield, Insurgency, Arma

Like arena based shooters? Quake, Unreal Tournament

Classed based shooters? Team Fortress, Insurgency, Battlefield

Multiplayer Survival? DayZ, Rust, and H1z1

Historical shooters? Red Orchestra, Day of Defeat

Tired of shooting and want to use melee weapons instead? Chivalry Medieval Warfare/Deadliest Warrior is a fun and brutal multiplayer first person slasher.

Junk>CSGO

I could recommend You just one game which still has not been mentioned yet. It's BlockStorm.
I've played it just a bit but it's basically CS:GO combined with Minecraft with few differences. Who knows, maybe You'll like it? :)

Loadout was pretty fun back in time. Don't know about the present situation but I guess it's worth a try.

Rising Storm

Borderlands 2 (Not competitive, co-op only)

Fast paced FPS
Quake, unreal tournament, toxikk
Fast paced FPS are awesome, but too fast for my eyes xD

Battlefield 3 and Bad Company 2. both great games. and i guess BF4 is pretty good by now, too (stopped playing shortly after release due to bugs, never started again^^).

every fps is better than cs :o

Survarium is great alternative, played it for over 700 hours, one for the worst FPS ever, it's f2p and in early access for almost 2 years (still in 0.28 version, with +0.01 udpates every 2 months). Hate this game so much, but can't stop playing.

It's a high shame that almost no one plays it anymore, but UT 2k4 is far superior to CS:GO. One that is played and is also free 2 to play is Quake-live, the amazingly well-done remake of Quake 3 Arena. A classic brought back to life. TRY IT!!! You could also try the multiplayer of the first Serious Sam game. Only game where you can shoot people with a fucking artillery cannon. Don't know if you'll still find someone playing though. Same goes for Half Life Source Deathmatch...fun, but deserted.

The counter strike series are still awesome games, especially for LAN parties :P If you have a slower machine, settle down with Counter Strike Source. If your machine can handle it, go for Counter Strike Global Offense. Awesome games, though me personally I don't bother with CSGO items. Waste of money ;) I haven't found anything better but I don't play a large variety of games on steam usually so yea.

counter strike source

I personally prefer TF2 to CS:GO, but that's really a matter of taste. CS:GO is a bit more, shall we say, "hardcore", you die easily, and the game punishes you for dying quite harshly (have to wait until the round is over, and you lose your weapon), which requires you to play carefully and also focus on cooperation. In TF2 death means less, so you can just run in and shoot stuff (and hopefully take down more enemies). Teamwork is of course encouraged, but the game has a more casual feel to it.