"do visitors mainly go to the www or no-www version of your site?"

Visitors follow links - just checked netlify.com vs www.netlify.com and over the last 3 days around 0.5% of visits went to netlify.com instead of straight to www.netlify.com

It's generally far more important to setup your site to be as performant as possible and get the best uptime than to skip the the www - there are ways to get the best of both worlds however.