Pros and Cons of site definitions over custom templates

Customization of site definitions holds the following advantages over custom templates:

• Data is stored directly on the Web servers, so performance is typically better.

• A higher level of list customization is possible through direct editing of a SCHEMA.XML file.

• Certain kinds of customization to sites or lists require use of site definitions, such as introducing new file types, defining view styles, or modifying the drop-down Edit menu.

Site definition disadvantages include the following:

• Customization of site definition requires more effort than creating custom templates.

• It is difficult to edit a site definition after it has been deployed.

• Doing anything other than adding code can break existing sites.

• Users cannot apply a SharePoint theme through a site definition.

• Users cannot create two lists of the same type with different default content.

• Customizing site definitions requires access to the file system of the front-end Web server.

• Once you build a site from a site definition, you cannot change it to a different definition later. You can still tweak it with additional features, but you can't change the "kind" of site it is. So you need to plan for its entire life-cycle.

Custom templates hold the following advantages over customization of site definitions:

• Custom templates are easy to create.

• Almost anything that can be done in the user interface can be preserved in the template.

• Custom templates can be modified without affecting existing sites that have been created from the templates.

• Custom templates are easy to deploy.

Custom template disadvantages include the following:

• Custom templates are not created in a development environment.

• They are less efficient in large-scale environments.

• If the site definition on which the custom template is based does not exist on the front-end server or servers, the custom template will not work.