Nice intro! A few questions:
* how soon are you planning to add support for aggregate/windowing UDFs? On-line docs talk only about row-wise UDOs - user defined operators. Since choice of windowing functions is currently limited, you should at least allow developers writing their own
* are there plans to provide "local" mode for U-SQL dev and test scenarios (similar to local mode for Hadoop, dev simulators for Netezza and so on)? Perhaps you can add it as part of the Azure SDK with a local emulator.
* what's the feedback channel for U-SQL?