Everything is full of buzzwords these days, however as.net is not considered that 'cool' compared to open source techs.
What does asp.net offers tha other don't? Let's see:
1. Visual Studio. Having used other IDE's from Zend, Netbeans, PhpEdit to Flash BUilder, Flash DEvelop, VS is way above (coupled with some plugins like ReSharper) although when using it you'll have the impression it's slow and bloated. It may be, but every time I'm using another IDE I want back to VS.
1.a. VS has good support for Htm and JS code completition so it helps you write those faster (I don't mean design mode, dragn'drop stuff)
C# . A beautiful type-safe language with support for generics, lambda expressions, extension methods, synctatic sugar and good performance.
There are MVC frameworks in php, ruby etc, however asp.net mvc gives you the power of .Net and a simple , easy to understand and easy to use MVC framework. Coupled with Razor view engine, you'll write readable code much faster in your views.
Linq2(Objects|SQl|etc) - Php (I don't know about other languages) has somekind of a clone but it can't match the original's flexibility and performance.
Higher producivity - All above helps you develop faster, from the IDe to the framework and language. WHen I have to code some php or action script my productivity decreases with at least 25% due to those factors. I can give you concrete examples if you want.
Excellent Performance - Yeah, besides the whole asp.net is compiled there are other ways to improve its performance:
- you can choose to skip lots of asp.net classic or MVC components and write only in handlers (kind of php way).
- You can use [unchecked and [URL="http://msdn.microsoft.com/en-us/library/chfa2zb8(v=VS.100).aspx"]unsafe](http://msdn.microsoft.com/en-us/library/a569z7k8(v=VS.100).aspx) code.
- You can generate IL (bytecode) on the fly (think of it almost like writing assembler) to create dynamic high performance methods, classes and assemblies.
For now, that's all it comes to my mind.