Izzet Prowess OR Eldrazi Tron for a newcomer to the format - which to buy?

Hey there,

This is a follow-up to my previous post here: https://www.reddit.com/r/ModernMagic/comments/1rgmjsr/starting_out_in_modern_dont_know_how_to_start/

I thank first to those who commented for their disposition to help, after reading the many comments I've narrowed it down to UR prowess or Eldrazi Tron as my first deck to have on paper for Modern.

I've got almost enough money for either one, but I'd like to further ask, which one is best for someone new to the format. I'm looking at participating in my LGS modern nights and RCQs and having a reasonable chance at winning and not having a bad time with my deck choice.

I accept all comments and suggestions. Cheers!