On any media or JS heavy site, Firefox on Android lags. Also for whatever reason small stuff like text boxes, zoom, keyboard pop up and tab zoom out animations have significant jitter. UI elements seem to be out of step with platform conventions. It's not the sort of thing that's easy to file a bug report for but you need a staff UX and performance engineer to go over it with a fine toothed comb to iron out the bugs. The current version feels very raw. You get the same vibe as a poorly optimized React Native app. Slight jitters here and there and a dropped frame on some animations. There is plenty of small stuff like the tab switching animation that feels slow. Nothing that will show up on a screen recording but immediately obvious if you are switching between Chrome and Firefox running on the same device. I suspect the root cause is that Firefox implemented a significant part of their UI in JS/HTML instead of native but I haven't checked the source code so that's just a hypothesis. On 2026 flagships, there's no excuse for it not to have a butter smooth UI (Oryon core chips are approaching laptop level of performance).