Its a very useful Add-On and works great so far! The Momentum feature works great too, even its a bit choppy sometimes and could be a bit smoother - but i'm not sure if its the Add-on or just my PC/Firefox @55.0b7@64 bit.

EDIT: Alright, it works flawless and butter smooth after enabling e10s@7 instances with following settings:

Grab and drag (like on a smartphone): 1
Momentum enabled
Page weight: 300
Additional speed: 0
Additional duration: 0

Advanced momentum setup:

Compute from last: 50
Mouse stop detection: 30
Tracking speed: 5
Smoothness: 1

Keep the great work going Juraj!