Have seen some bugs, but the one I would really like to be fixed is the frame rate drops as the simulation is running, it doesn't matter if you are by buildings or with just terrain around, every 6 seconds I get a frame rate drop that lasts a second.
Making it not smooth. I use to love the smoothness of the earlier version.
I hope they optimize the sim for better performance before they add more stuff too.
This happens on my iPad Air 2 regardless of graphics settings set to high or low.