So I'll be joining fresh into 40k with a group of friends in Oklahoma who already play. I understand how most of the basics work, but my curiosity lies with choosing an army. Off the bat I read about the armies and their back stories and what they actually do and how they play. The ones who peak my interest are the Thousand Sons/Demons of Tzeentch, The Black Templars, and the Tyranid. My question is out of experience of the people on this website, what are the pros and cons of each?