.Net is language independent. If you are a C++ developer or VB developer or C# developer or F# developer you can easily work in .Net.
.Net framework provides you a lot of library files for easy use and we can develop the application faster than developing in Java.
.Net technology has a tool called VISUAL STUDIO to develop the front end designs which makes us to finish our work faster and easier.
We dont need to code for the UI designs.
To use the .Net application in other platform, we can go for the web application asp.net.
There are many .Net languages are available like c#.Net, VB.Net, f#.Net. C++.Net, python.Net, Ruby.Net etc...
Thats why .Net is widely used!!