Myself, and my experiences, it matters much which airports you go through, and perhaps your personal details.
I have been through the Schengen area a couple times this year, it really took no more time than other times I was through, but then I went through AMS, I would dread going through Lisbon (been there a couple times before), and they were a mess years ago, and I doubt it has improved.
My personal observation is that it has worked great for my wife. She goes to the kiosk, scans her passport, takes a picture, then directed to the e-gates, and she is out in 5-10 minutes. Myself, I have a problem, I am missing part of my index and middle finger on my right hand, so I am asked to scan and rescan my fingerprints (usually tells me I am using my wrong hand) then after a few attempts, it tells me to go to the manual lines, and that is what takes time.
Other than that, EES is a non-event, even going to the manual lines, is only maybe a 20 minute exercise, no difference really than before.
Now if your Schengen first stop is Germany, be prepared to go through a manual line, for other reasons.