InstallScript projects use the InstallScript language to control the installation.  You may want to choose InstallScript and exploit the following features:

• The InstallScript language is easy to learn.
• In this project type, you can display full-screen billboards (background images).
• This project type makes use of the InstallScript language, which allows you to write a procedural installation rather than author a set of tables.
• The InstallScript installation type is easier to learn than the Basic MSI installation type.    Actually, the learning curve for InstallScript is much less than that of Basic MSI.
• InstallScript allows you to perform actions before or after the main installation has run, meaning that InstallScript makes use of an event-driven model, which is useful if you're used to programming for Windws.
• You will have to work with InstallScript if you are given an existing InstallScript installation to maintain.
• InstallScript projects don't use the Windows Installer, which means your product can not be submitted to the Certified for Windows Vista Logo program.

Basic MSI projects use the Windows Installer service to run the installation.  You will want to choose this project type for the following reasons:

• You want to submit your product to the Certified For Windows Vista Logo program.  One of the main requirements is that you must use the Windows Installer for your installation.
• You don't want to use a scripting language for your installation.
• You have to work with Basic MSI if you are given an existing Basic MSI installation to maintain.
• You want to maximize compatibility with administrative tools such as Microsoft SMS.
• Your software will be customized by system administrators prior to release.
• You want to create transforms for the installation.  A transform is used to modify an existing installation project.
• There is more of a learning curve associated with learning Basic MSI installation development.

If I were just learning how to use InstallShield, the first question I would ask is whether my company wants the Vista logo on its product.  If they want to meet the Certified For Windows Vista program requirements, then you have no choice but to use the Basic MSI project.  End of story.  In the end, Basic MSI installation development has more of a learning curve, while InstallScript installation development is pretty easy.

Hope this helps.

To watch free tutorial movies on InstallShield 2009, please visit: http://www.wavepointstudios.net/msi-2009-videos.aspx