This is what I learend:
> NEVER pick Alicia. EVER. You will fail. To win as an antagonist, you need to at least have the option of stealth. But Alicia is incapable of winning because she has 100% aggro at all time so they will always be able to see you through walls.
> NEVER try to fight the Host in anything but surprise melee. They are several seconds ahead of you, and their commands take priority over yours. You cannot dodge them. You cannot grapple them. You cannot win unless you surprise them, which you cannot do as Alicia.
> NEVER fight Konstantin. His gravity ability is massively overpowered against Antagonists. The only way to kill him is to sneak up on him (Which, again, you can't do that as Alicia.) and even then its hit or miss since he'll just blow you away with gravity and obliterate you as you float helplessly for ten minutes.
> Shae and Harec are the only characters you can safely approach at close range and expect to beat in melee.
> Respawn points are extremely limiting for the Antagonist. For the most part you can only spawn and approach the raiders from the same side every time, so they can expect and prepare for you coming.
> The invincibility period is a severe detriment to antagonists since you can't attack but are still highly visible. Basically just means they'll camp your invincible body and blow you away frequently.
> There is no point in playing an Antagonist. You get zero rewards. It just wastes your time.
> DO NOT pick Alicia. I cannot stress this enough. If all the above reasons did not convince you, then I encourage you to try it and see how severely she fails.