First time we were going to have a short connection on what I thought would be a busy day (Memorial Day) I signed us up for global entry. Hasn't really made a huge difference, but its probably saved us anywhere from as little as 5 minutes to as much as 15-20 minutes or so.

Plus with global entry you also get TSA pre-check, so if you travel at least yearly, I think its well worth it. Even more so if you travel more frequently.

We did see someone who only had an hour between flights make it one time though, so it is doable.