Building Free-threaded components is not recommended; if possible, you should use the Both model instead. One disadvantage of Free-threaded components is that you must register them with the MTS explorer in order to access the ObjectContext object, whereas all Both- or Apartment-threaded components can access ObjectContext. This means that Free-threaded components that you have not registered with MTS explorer can only access the ASP built-in objects through the ScriptingContext object. This method of accessing the built-in objects is considered less suitable for ASP components than using ObjectContext. For more information, see accessing the ASP built-in objects.
The final problem with Free-threaded components is that, like Single-threaded components, they run in the SYSTEM context, rather than the context of the logged on user. As a result, the Free-threaded model is not acceptable for scenarios which will rely on Windows NT® security to control access to objects.