What are the advantages/disadvantages of the various style methods?

Advantages

• Can control styles for multiple documents at once.
• Classes can be created for use on multiple HTML element types in many documents.
• Selector and grouping methods can be used to apply styles under complex contexts. 

Disadvantages

• An extra download is required to import style information for each document.
• The rendering of the document may be delayed until the external style sheet is loaded.
• Becomes slightly impractical for small quantities of style definitions.