While the recently released XDA-Developers app is a nice addition to the WP7 Marketplace, it has some lagginess that can ruin the experience.
For just $0.99 you can buy the newly released XDA-Developers app. This app is essentially Board Express Pro, but only with XDA-Developers loaded. So for a little more, $2.99, you could buy an app that lets you view all of the compatible forums through one app. But if you only use XDA, the specific app is just perfect for you.
In the app, you can login to your account, view/respond to personal messages, view your unread/subscribed/and participated in threads, and reply to posts. The app essentially has everything the true XDA site has. The only thing that is missing is the lack of formatting options when replying to threads. You can quote people just fine, but unless you know the forum codes for [b]bolding[/b] text and other formatting tricks, you won’t be able to format your posts. That is of course a very tiny thing, and most people will not be worrying about formatting from a phone.
However, what is important is that the application can sometimes lag. This lag seems to be the worst after you have swipped through a few different horizontal screens (like the Forums, Settings, Search screens). Then, the application can take up to a few seconds to actually respond to your touch. If you open the XDA-Developers app just to check and reply to new posts, then it should run plenty fast. But once you start to do more things inside the app, it starts to slow down.
If the lagginess ever gets improved, the app will be really great. However, the lag seems to be an issue with Board Express in general, since the full app that includes other forums is just as laggy. You can find the XDA-Developers app in the Marketplace for $0.99, or the Board Express Pro app for $2.99