Imo the best mercs I like to use, would be Aura, Fletcher, and Skyhammer. Also I would say the game is more like pay2convenience, considering the 2 mercs you get at the start are so loving crucial to your team. Nothing is more frustrating than a Skyhammer not giving you ammo as you yell ammo in the teamchat and forces you to go melee just to be shot down moments later. In general this game is more reliant on teamwork when you get into ranked matches, because if there isnt an Aura or Sparks on a team, theyre prob screwed.