Measuring Frame Uniformity
Enable the preference 'layers.uniformity-info'. Then you will get a lot of spew in adb logcat. Next, update and install orangutan - https://github.com/wlach/orangutan.
Then, run orangutan to create a scroll. At the same time, make sure you have adb logcat open. Copy / paste all the logcat into the frame uniformity tool:
Then push Reload Data, which should give you a graph of frame uniformity. The smaller the difference in frames, the better. The mean and standard deviation are reported by the frame uniformity tool. The lower the standard deviation, the better.