Its simple - you only have 2 troops choices, and thats either Warrior or Wych. And its Warrior.
They are very versatile, they have mobility in their transport, they are able to hurt absolutely any foe in the game with the combination of poison and blaster. Lastly they are a cheap points wise.
Either you will be taking raider or venom, both are good and serve purpose.
They are core and backbone of any force. I prefer 5 man squad with blasters, so i have 4 squads in venoms and 2 more in raiders.
Blasterborn are good becuase they are basicly the warriors that can take 4 blasters, and blaster is a very good weapon. It can hurt tanks and heavy infantry and monstruous creatures.