why .net is better

Java and C# are based on C++; their syntax and such are very much alike. PHP is based on C; it is not object-oriented or at least not when I was learning it years ago. I think PHP has been improved but you need to consider whether PHP is adequately object-oriented.

Java is proprietary. That is what the legal fighting was about between Microsoft and Sun before Microsoft designed .Net and C#. C# and the .Net library are international standards (I think the standard calls it the CLI). Sun won't allow other companies to improve Java if Sun does not approve. So your choice whether to use Java and the Java Virtual Machine or to use .Net languages and the CLI or whatever it is called is partially a matter of principle (your opinion of the legalities), not technical.

Something which I experienced in working in .Net
Best language support i.c C#,VB.Net cause interesting in programming.
Visual Studio provide something like what you see is you get support means design as your wish.
No issues of memory management except some cases.

It's a long list. Here are a few top of my head 

.NET has -

• C# - Most advanced, well thought and the most beautiful language
  
• Smart people like us :)
  
• Much faster development
• Best IDE Visual Studio 2010
  
• Supports all Windows, Web, Components, Services
  
• Backed by Microsoft