Choose by platform mix and who maintains the suite. Espresso (Android) and XCUITest (iOS) run closest to the platform and are the fastest and most stable, but each covers one platform, so you write tests twice. Appium is the flexible cross-platform option with multi-language support and a large ecosystem, at the price of more setup and maintenance. Maestro uses simple YAML flows and gets teams started quickly but is less suited to complex scenarios; check its current iOS support in the docs, because real-device support has lagged simulators. Detox is the usual pick for React Native. Speed claims such as "3-6x faster" come from vendor blogs, so benchmark on your own app.

Sources: Espresso, Apple UI tests, Appium docs, Maestro docs, Detox, Autonoma comparison