After having the 6s since launch day, I'd rather use my iPhone 5 running iOS 6.1.4. It's just so better and more fluid. It also looks better too. I'm sick to death of iOS 9 crashing and lagging, and especially the stutters in the animations. Seriously? My iPhone 5 a 2012 device feels so much more responsive running iOS 6.1.4, I don't know why that is, but its very noticeable. Even a coworker saw the difference. And for the record, I was running iOS 9.2, beta 3 on the 6s, and before that, 9.1, with very minimal changes in the performance.