> I've had more problems with Widgets, especially when doing a lot of animations (even just scrolling big text views) on a 4K display on MacOS, but maybe I'm thinking graphics and not input lag.
There's two things to consider when comparing rendering performance: throughput and latency. Throughput, or how much FPS the engine can sustain, is much better in QML since it's leveraging the GPU, but latency it's very platform-dependent. Mac is actually the one where QML does best in terms of latency (and by that I believe it approaches the latency of Qt Widgets), since it's synchronizing with the VBlank signal provided by CVDisplayLink. On Windows and Android the situation is worse.
There's two things to consider when comparing rendering performance: throughput and latency. Throughput, or how much FPS the engine can sustain, is much better in QML since it's leveraging the GPU, but latency it's very platform-dependent. Mac is actually the one where QML does best in terms of latency (and by that I believe it approaches the latency of Qt Widgets), since it's synchronizing with the VBlank signal provided by CVDisplayLink. On Windows and Android the situation is worse.