OK, so if I understand your question, you basically want to know the advantages and disadvantages of php, asp.net and other similar technology.
An over-simplified explanation of typical scenarios is:
asp.net = c# is written in visual studio, compiled and then run on iis. The advantage is that c# is a nice language with some good features, the disadvantage is that you don't get a whole load of cool open source components.
php = php is written in whatever text editor you like most and run with an apache module. The advantage is that it is easy, the disadvantage is that it is easy to get something that works but is low quality.
java = java is written in eclipse or netbeans, compiled and run on tomcat. The advantage is that it can be the best of both php and asp.net but without the disadvantages, the disadvantage is that there is so much available for it that you have to be really selective and know what you need.
Of course, this is very much glossed over and there is infinite complexity here if you're willing to get into it.
