Tried running ArcGIS Runtime SDK for iOS samples from the GitHub with XCode 9 GM Seed and iOS 11, the map rendering performance is really slow. If I try to zoom in/out or browse around my location the rendering animation is killing UX.
Turns out this is due to a bad Open GL ES library.
Temporary fix is to pull those libraries from an older beta of XCode and drop them into your current XCode bundle... sounds scary but it isn't. Links to those files as well as instructions have been posted to Redit here:
This fixed it on my MBP running High Sierra and XCode 9