Pros and Cons of MDA Code Generators?

amartel asks: "Four years ago, Ask Slashdot asked if anyone was using a Model-Driven Architecture. The number of MDA tools are now almost overwhelming, and I strongly believe that comments to the same questions would be rather different nowadays. What are the drawbacks, difficulties and limitations of MDA? What percentage of code can actually be generated? I would like to add a few more: is it realistic to create a custom GUI rather than CRUD operations with these tools? Finally, what about Microsoft, the new competitor on the scene, and their DSL Tools?"