I ordered Metronet this weekend. They're just building out my part of town so it's probably a couple months or more before I actually get it. But I found this article pretty instructive in deciding which speed to get. It's the Wall Street Journal so it may be behind a paywall, try opening in an incognito window or accessing it through a Google search.
www.wsj.com

The Truth About Faster Internet: It’s Not Worth It
WSJ testing shows typical U.S. households don’t use most of their bandwidth while streaming and get marginal gains from upgrading speeds