I haven't tested this, per say, however I've noticed that Firefox is noticeably slower and buggier than Chrome or other webkit-based browsers. whether or not that is due to the parent or the engine I do not know. I still use Firefox, however, thanks to Google and Microsoft constantly pushing me to use their stuff. If Google could have stuck with Chromium/webkit/related tech being open source with no motivation, I would have never switched.

As it is I still have to open up edge to get decent quality streams from Streaming sites because Firefox doesn't support the DRM used.

The actual biggest gripes for me:

* tabs can, and do, crash. When this happens, pots luck on whether the browser can recover or not. * NVIDIA driver updates on Windows almost always cause Firefox to stop rendering stuff prior to reboot. Edge and Chrome do not have this issue. While I can somewhat understand, Mozilla should warn users. I've updated several times across 4 NVIDIA GPUs and I've had this issue. Firefox has asked me to restore tabs exactly once. The rest of the time they were gone. * The really odd theme of the day is that hitting reload on Firefox shows signals that it is reloading, but it never does. If I duplicate the tab the site loads fine. Dev console shows no errors. Firefox is at least 10% slower on major sites like twitter, etc. vs chrome/edge, as of my last test.