In case you missed that - the new Beta SDK for Windows Phone 7 is ready to be downloaded.
Some new features under the hood and many incompatibilities to the CTP version regarding namespaces and XAML tags. There is are nice porting guide out which helps to get your existing app rather fast over to the new version.
Microsoft stated that its more or less final reagarding the API. No mayor changes will be coming to surprise the early developer.
I tested an issue with WebServices and SOAP - and its still not working correctly if you consume a (Sun Glassfish hosted) SOAP WebService which returns an array of a little structure. For simple types like returning a string it works fine. Hope they will work on that till release.
I ported over my littel app MyDietLog. Was not bad - it only took some time to figure out, where the main app screen will be actually started. They changed alot in the app.xml.cs and manifest files.
I got even an answer from one of the OData guys gegarding complex LinQ queries. They are simply not working because WP7 currently is not supporting Linq closures (if I got it right). So he gave me the tip to just use a different approach and construct the Uri string by hand. Works nice and I could speed up the app significantly.
Last but not least - the emulator comes without the MS apps preinstalled (at least they are not activated as usual) - and it has a nice new skin (a little bit smaller). It seems to load much faster from Visual Studio too...