 <p>The short answer:</p> <p>the .net platform can be used for transactional systems, but the question is really is the platform scalable enough and can it perform well enough under extremely high volumes?</p> <p>.Net like every other high level language has a place in this world, and I personally would not use .net managed code for core transactional systems. In the same way I simply would not use .net for writing mission critical device drivers. </p> <p>If you have a choice go for c++ for mission critical stuff. Don't throw .net out of the solution entirely, recognize it has its strengths, and use it accordingly.</p> <p>.net is very good for rapid, reusable development, I would even say if you use it correctly (perhaps even go unmanaged) and test / retest your apps, you'll get away with a lot more than you think. </p>