Imperialis or Titanicus

Hi guys, need your help. I want to gift my dad a GW board game, as we are both fans of 40k, I can't choose between Adeptus Titanicus or Legion Imperialis. Which one is beginner friendly, which one have the simplest rules, I want to play easily, with not so many Times of setup. Which one is more easy tonger into ?Also, which one is cheaper on the long term. ( I'm french i don't think there is a french edition of Titanicus ) So, what are the pros and cons of each ? Help me choose ! Thx ❤️