I suppose it depends upon what the definition of "lag" is. If it's a 50ms difference in touch response on some devices, that is quite a change from the historic

I suppose it depends upon what the definition of "lag" is. If it's a 50ms difference in touch response on some devices, that is quite a change from the historic meaning of lag. Lag historically was a significant delay between interaction and response. It was also continual stutters and variances in interaction speeds. But by Android 4.4 and the N5, that is generally annihilated. Paradoxically at the same time iOS 7 on my 3rd generation iPad has brought Android 2.x-style lag to that platform -- I now have an experience on it where keyboard presses respond 700ms later, and other activities have completely unpredictable delays.