I’ve used both pretty heavily, and what sold me on Playwright was the cross-browser and debugging experience.
It’s dead simple to spin up tests in Chromium, Firefox, and WebKit with the same script, and the trace viewer is a lifesaver when trying to debug CI failures.
WebdriverIO has grown a lot, but it still depends on the WebDriver protocol, which can introduce latency and some weird edge cases.
Playwright’s browser context model also makes test isolation much easier.