APP_CODE vs Class Library

Basically, beginners like me, love app_code, like the writer below, i too experience slowness in VS, when i use APP_CODE, so now it makes more sense, so anyways the article below explains why app_codes slows alot of things down, once very critical thing about app_code is (if one class has err, whole side GOES down) unlike class library..

Source: http://devlicio.us/blogs/brendantompkins/archive/2006/09/22/Speed-Up-VS-2005-Web-Development-_2D00_-Kick-your-App_5F00_Code-Habit.aspx

Every time you make a change to a file in the App_Code directory, this invalidates the Visual Studio's internal cache of classes in this folder. The very next time you try to open a designer for an ASPX page or ASCX control, VS has to re-compile this folder to get the metadata it needs for the design-time rendering of the control. This can cause the IDE to slow to a crawl.  One the classes are cached, things speed up significantly in the IDE.


Info about Bin & AppCode as explained by MSDN:
http://msdn.microsoft.com/en-us/library/t990ks23.aspx