After spending some time working with WP7 now, I really must comment on the embeddable web browser, the WebBrowser component. As a recent convert to WP7 as a user, I can't say I've too many complaints about the phone's main browser (Internet Explorer, as you may have guessed) and it usually does the job fine. In my heart, I know it could be much better, much smoother, support many standards better, be... much more like a Webkit browser really!
However, having found a requirement which could have been satisfied with either native components, or the use of the embeddable web browser, I opted straight for the web browser route. The reason for this, mainly, is that this solution has been used across iPhone, Android and BlackBerry with little or no tweaks needed on the server side when integrating the new platforms. Take all the content needing shown, use HTML to handle the layout (optimised for the requesting device, of course), wrap it all up and send to the device which can store it locally for offline viewing. Elegant, efficient, flexible... perfect. And best of all, changes to this layout requires no code changes, so can be edited even after the apps have went live. Beautiful, I must say, even though I can't take the credit for the original idea. Cue WP7 deciding to be a bit special.