Over iOS 11. And I encourage you try try iOS 12; I've been using it for three months and it's been really fast in my experience.

There were issues with the scheduler in the kernel code in iOS 11 that IIRC had lingered since iOS 7. The difference can be pretty remarkable. Basically iOS can ramp up resources where they are needed much more quickly, so one might say it’s using the CPU more efficiently. It eliminates a lot of stuttering for me. I was worried it might come at the cost of battery life but I haven’t seen many differences there besides some iteration during the beta.

Been using the beta on my 6S for the last month or so and the speed increase is noticable.

The keyboard especially feels faster and more fluid.

They’re definitely wanting to shut down the ‘apple slowed down my device!!1’ narrative with this one.