Maybe the S6 is the first example of a turn-around for Samsung. However, HISTORICALLY, Samsung devices have gotten worse/laggier with each update. You've had your S7 for, what, 3 months? Hardly enough time to form an opinion about the long-term snappiness of the device, especially after OS updates. Take my tablet that is just over 2 years old, it was a YEAR before Samsung finally released Lollipop for it and the performance of it is hit-and-miss. Oh yeah, it's also now stuck on Lollipop as Samsung won't give it any MM love. Meanwhile, M appears to be the end of OS support for the 2013 Nexus 7 but that device IS now 3 years old. Oh yeah, the Nexus 7 will likely continue to get monthly security updates for another year which is more than can be said for a Samsung device as Samsung has not yet proven it will keep up with the monthly cycle.
Yes, I was talking about that because it shows a lack of long-term support for devices.