Stalin V trostky

Id like to have some opinions on the struggle for power between these two key figures in Bolshevik Russia. Trostsky's weaknesses or Stalins strengths? Remember if th Politburo had followed every word of the Lenin (as they stated to when they intriduced the Lenin Legacy) Trotsky would have been put into a position of power whether he had wished it or not and Stalin would have been ejected after Lenin's death.