[JonnieCache]

I'm on ff 40 (developer edition), so presumably I've been running project silk for a while now, and for me the scrolling is visually indistinguishable from chrome. The difference is in the inertia: chrome slows to a halt marginally more smoothly, and it does that thing where you can elastically scroll past the end of the page.

The increased smoothness of the inertial model probably indicates that chrome's scrolling is actually better, repaints more closely aligned to vsync or whatever, but like I say there are no actual artifacts, tearing etc. visible on my macbook retina. If you've got a top of the line 120fps gaming monitor its probably more noticeable.

That fancy lcd-testing website probably has some way of measuring it.

For me the big issue is the lack of visual feedback when swiping left and right to go back and forward. In chrome/safari you get a big sliding animation to tell you you're triggering the gesture correctly. In FF you just get an arrow after the gesture has been triggered, when its just annoying visual clutter. This means it still sometimes takes me multiple attempts to hit it, because I don't have that feedback during the gesture to cement the muscle memory.

EDIT: apparently chrome gives you the arrow, ff gives you absolutely nothing.