Got GE earlier this month - had final interview at Champlain on US/Canada border. 15 minute interview by a very friendly TSA agent, and received my email later that day approving my application.

Couple of things to note when first used:
passing through Montreal en route to Chicago I couldn't use fast track security as the Canadian insisted on me showing my GE card - I don't have one as it is held electronically on my UK passport. Was advised that is the case throughout all Canadian airports when travelling to the USA. Hopefully this will change as more people have their GE stored electronically.
However, having finally got through fast track security another way, I rolled up to the clear US immigration, headed to the electronic machines and (1) scanned my passport, and (2) did my fingerprints and was straight through - extremely speedy and a welcome relief from the usual queues.

Unfortunately, as others have already noted, you don't always get TSA Pre as it is dependent upon airline. BA don't do it, and at ORD, T5 doesn't have TSA Pre at all.

Useful link here as to what airports/airlines have TSA Pre: https://www.tsa.gov/precheck/map