the difference between JSP and JSF:

1. A developer has more control with JSP, but (should) get easier development with JSF
2. Event handling is done differently in JSP (HTTP) and JSF (Java)
3. The UI is designed differently (or should be at least) with JSP (markup) and JSF (components).
4. The end product should also be defined differently - JSP page versus a JSF application.
Is this the only thing that is need to make a decision for either or? Probably not. There are other pieces that need to be taken in account when deciding which technology to use - tools support, enough components, type of application etc…. At this point there are not enough JSF components (although there are some interesting projects underway - Ajaxfaces, Myfaces, ADF Faces, and WebChart 3d) and enterprise tools support is still limited to a few tools vendor. Looking at our ADF Faces components they are currently available as early access (not production) and demands for these components are stacking up, literally, outside my office doorstep. Although I would love to make them production - now! - it is not a viable solution since we are still checking features and fixing critical bugs.
All this combined - not enough enterprise level components in production, lacking tools support etc… - leave customers in a vacuum where the decision is either to continue with JSP, since it is mature and has a wide developer base, or move forward with JSF not sure if the support, or the developers will be there. This is particularly sensitive to customers that need to get started now and be production by summer.
If you are in this vacuum here are some key points promoting JSF:
1. Fundamental unit is the Component
2. Built in event and state management
3. Component sets can be provided by any vendor
4. Closer to ASP.Net or Swing development
5. Choice of UI technology
6. Scale up (rich clients)
7. Scale down (mobile devices)
8. Built into J2EE containers in J2EE 5.0 (tentative)