Volibear or Hecarim?

They're both tanky with CC and damage but which would you rather have on a team? Which one would be better suited for climbing?

edit: Both are frontlines but I feel like Hecarim's main objective is to fear the team and take out the ADC while Volibear has his regen passive and flips any squishies in range (I.e an assassin that has run out of escapes, squishy mages that have no way out)