If you are looking to build a large/enterprise scale application with lots of features i.e. User management, databases, caching, cross-platform then ASP.NET is definitely a way to go. As ASP.NET is developed by Microsoft, so there is no native support for Java or Python or other programming languages. That becomes a barrier sometimes when you are working for a company who's tech stack doesn't really work on Microsoft technologies.
I would recommend Mendix for large organization issues and applications. It is very robust and scalable. It is made to deploy quickly so changes and expansions can be made every step of the way. I would not recommend Mendix for very small projects because the costs of usage would just be too high.
A 10 would say I have nothing to wish for. A 9 means I haven't seen anything better.This tool really helps you in the whole creation and maintenace cycle, so from requirements to building/modeling to testing to deploying to capturing feedback.
Response times are quick and you will get updates regularly about the status of your request. Even with very technical questions they have specialists that can help you with your problems it will give you an answer or help you with a work around.
We selected ASP.Net because of the market position. It is well known in combination with visual studio and IIS. Also, new colleagues know this and can be involved very quickly. No need to make a lot of investment in education. We do need to teach them the guidelines of our company.
We evaluated 3 to 4 other products before making the choice to go with Mendix. From a maturity perspective it was further ahead than the other options. From the rapid development perspective the tool was light years ahead of others. The ability for developers to learn the tool quickly and still have the flexibility within the platform to develop simple to complex widgets is great. This tool has endless possibilities once you become comfortable with the platform itself