Compare JSF and Struts

Advantages of JSF (vs. Struts)
Custom components
JSF makes it relatively easy to combine complex GUIs into a single manageable component; Struts does not
Support for other display technologies
JSF is not limited to HTML and HTTP; Struts is
Access to beans by name
JSF lets you assign names to beans, then you refer to them by name in the forms. Struts have a complex process with several levels of indirection where you have to remember which form is the input for which action.
Expression language
The JSF expression language is more concise and powerful than the Struts bean:write tag.
This is less advantageous if using JSP 2.0 anyhow.
Simpler controller and bean definitions
JSF does not require your controller and bean classes to extend any particular parent class (e.g., Action) or use any particular method (e.g., execute). Struts does.
Simpler config file and overall structure
The faces-config.xml file is much easier to use than is the struts-config.xml file. In general, JSF is simpler.
More powerful potential tool support
The orientation around GUI controls and their handlers opens possibility of simple to use, drag-and-drop IDEs

Disadvantages of JSF (vs. Struts)

Established base and industry momentum
Struts has a large core of existing developers and momentum among both developers and IT managers; JSF does not.

Support for other display technologies
JSF is not limited to HTML and HTTP; Struts is

Confusion vs. file names
The actual pages used in JSF end in .jsp. But the URLs used end in .faces or .jsf. This causes many problems; in particular, in JSF

You cannot browse directories and click on links

It is hard to protect raw JSP pages from access

It is hard to refer to non-faces pages in faces-config.xml

Self-submit approach
With Struts, the form (blah.jsp) and the handler (blah.do) have different URLs; with JSF they are the same. Many developers find this clumsy.

Less current tool support
Struts is supported by many widely used IDEs; JSF is not (yet)

No equivalent to Tiles
Struts comes with a powerful page layout facility; JSF does not
But you can extract Tiles from Struts and use it with JSF

Much weaker automatic validation
Struts comes with validators for email address, credit card numbers, regular expressions, and more. JSF only comes with validators for missing values, length of input, and numbers in a given range.
But MyFaces has several powerful validators
Lack of client-side validation

Struts supports JavaScript-based form-field validation; JSF does not
Worse installation

JSF does not have equivalent of struts-blank to start with

POST only
JSF does not support GET, so you cannot bookmark results pages