Take techcrunch for example, a ton of YC startups get their own stories. Meanwhile Techstars just gets a single big "here are some techstar companies" with a list of their top 5 companies.
Given the choice, go for YC.
Think of Techstars as your safety school. It's a great school, but deep down you know that the only reason you are going there is because you got rejected by the school of your dreams.