I hate Glass the most. Blackout I understand the hate, but if you're smart then you can just play at range and be constantly aware thanks to the audio of enemies. Grounded is just easy to deal with. Iron is just annoying, seeing as it takes 20 years just to kill a dreg. If you are using an auto, it feels like a pea shooter. But Glass is just horrible. You get instashot but almost every sniper in the game.