If you plan on traveling in and out of the country more then 10 times over the next 5 years, you have to get it, especially if you are single. You save time with TSA Pre-Check, no waiting in line so you can get to duty store quicker and sample the alcohols before your plane takes off. Coming back into the country, the passport lines are crazy long cause other planes besides yours are coming in. With Global Entry, you have your own machines to check back in with and a short line with the Pilots to walk into the luggage area. Sometimes they don't even man the GE booth cause they need help with passport lines. The time you save means you can hit the can and change shirts or wash your face before the luggage unloads.
I like being the last one off the plane, so I am not around the nuts that be rushing and cutting to get off the plane so they can get to the passport line faster. All of them that were rushing still don't beat me, cause I am able to bypass the passport line.