Bug-at gyud tinuod ang ASP.NET webforms, bay. Unsaon gi-model man gud ni nila sa windows forms nga stateful bisa'g stateless ang http protocol. Kun gusto ka'g mas gaan, limpyo'g agi nga framework, you can use ASP.NET MVC. Unlike ASP.NET webforms, an ASP.NET MVC application doesn't rely on viewstate. It embraces the stateless nature of http. Unya, like any other web mvc frameworks,
convention over configuration is encouraged. This means that if you follow the convention (ex. putting a 'Controller' suffix for all controller classes), you can create a fully functional web app in just a few minutes.
Just a note about licensing. You don't need specific license for ASP.NET. IIS and the .NET framework come with any 'server-based' Windows OS. Yes, you need to buy the OS license but similar case applies for Linux servers. Though free versions are available, most companies do not use them in the production environment. That is the reason why almost all linux distro's have their own commercial variant of linux (ex. RedHat's RHEL, Suse Enterprise).
Going back to the topic, I've been using ASP.NET for years (I've tried PHP before pero dugay na kaayo to nga panahon
) so mas comfortable ko sa ASP.NET.