many of us today chooses ASP.net coz it easy to make codes, easily to manipulate the classes and other tools, having a visualization of the of codes, it is much faster than PHP in term of result....
yet in comes of hard coding the PHP scripting is the best application to have, if you a are a hard coder, you manipulate the inside of your program hence determining the future problem...by the way it is free , and having APACHE and MYsql it becomes powerful...
yet for me it depends on the situation, if you have a lot of time use the PHP, if not use ASP.net, it either you want to finish the job or have a strong coding practices,still the you must run your program smoothly by the end of the day, no bugs or errors, well just a minor bugs......