iphone 6 plus

No lagging. Crashes all the time though.

My iphone 6 is fine during battling, so your 6s is definitely not the culprit of any lag.

I have a 5 and wife has a 6 plus. Lag isn't an issue but frequent crashing when scrolling to view mons in a tower and sometimes during battle when prestiging repeatedly.

I'm using an iPhone SE, which has specs similar to iPhone 6 but in the iPhone 5 case size.

Gym animations are fairly smooth. No drops in frame rate like with Water Pulse on iPhone 5.

Still experience the super annoying dodge bug (game thinks you missed a dodge, then decides you made it and refunds HP), but I think that is based on lag between server and client.