PocketNow sets up a browser test between the iPhone, Android 2.2, and a Windows Phone 7 smartphone. Note that the Windows Phone 7 software is still a work in progress, but the video is worth a look anyhow.
The browser of Windows Phone 7 seems to be on the right track. Tab management is super quick (you can even load multiple tabs simultaneously), website load times are competitive with other top smartphone browsers, and panning/scrolling/zooming is ultra smooth. If we can get HTML5 and Flash support in Widows Phone 7 and maintain this level of refinement, IE on WP7 will rock.
HTML 5? Sure. Flash? Not so much.