I can back up their first point a tiny bit with regards to canvas. The primary product of our company is heavily canvas-based so I’ve always noticed that canvas on Firefox on macs is slower than on Chrome but it used to be in the 2-3x range and nowadays is more in the 1.5x range. They’ve made great improvements and I’ve never noted anything close to 5-10x slowdowns.

On Windows Firefox and Chrome canvas has performed equally well at least for the past ten years. Got no data for linux tho.