Visual Studio.NET is the umbrella that represents the key pieces of the .NET platform delivered from Microsoft, including the .NET Framework, the recently announced .NET Core, and a shared common layer of packages, compilers and runtime. Read this .NET blog post about the evolution of the platform and the different pieces that make .NET 2015.
The Nexaweb Enterprise Web 2.0 platform has been used to modernize hundreds of client/server applications. It embraces open standards, is extensible and enables re-use. Furthermore, the Nexaweb Enterprise Web 2.0 platform enables customers to develop distributed, interactive, rich applications that require outstanding reliability and performance, such as those in financial trading, order management, product configuration, and business-to-business self-service.