Developing CLR-Based Stored Procedures

An excellent article detailing the whys and wherefores of managed stored procedure development; first off, they're slower (as you'd expect); they should be used as a "replacement for extended stored procedures not simple expressions", so you'd use them for number-crunching, cryptography, or for accessing resources not accessible to T-SQL, such as the registry, etc;

This explains a lot, and makes it clear what place managed stored procs have; but note that when you add a VS 2005 data project to your solution, the only kind of stored proc you can add to it are managed ones. This is going to have the effect of causing many devs to mistakenly believe that managed stored procs are the way to go, and start abandoning T-SQL, and running into some significant performance issues...