70% development time gain in using .NET
In building their website, Performance Products achieved a gain of 70% in development time (& also 75% in response time). It's good to track case studies with actual numbers attached to it - of course, there'll be skeptics, etc. but there is substantial benefit even if it were half-true! Keep a portfolio of case studies, it'll help sell .NET to your bosses and clients. The other point to note is the business benefits it brings by deploying .NET (increased sales in this case).