I really like the the direction the CRM Sdk is going, but there still are some serious issues with the 4.0.12. release.
Especially the wrong usage of Premature Caching is VERY problematic and can be the death of any application of larger scale. There is a messy workaround (http://social.microsoft.com/Forums/en-US/crmdevelopment/thread/2407e44d-9903-4587-8051-575388189cec),
but i really can't use such a broken access strategy to the data-layer for production.
There are also some other big concerns in using this SDK-Version (no usage in plugins, no linked entities-support in LINQ,...), besides some missing features like
count, authentication options and a code generator, which is not flexible enough (strip prefixes!?!).
I'd need to know if we expect an update anytime soon, before we extensively start using the official SDK.