Clip or Track Automation?

Good Day,
 
I’m wondering if someone could provide reference to info, or explain better (than Ive found in help doc), the use of, and pros and cons of using either "clip" or "track" automation for volume/pan, and possibly as relative to envelope/offset mode, or other features. Help documentation seems limited to saying there are these options available, but not much of why or when or relevance between functions. Apparently some fundamental things Im not understanding in the automation mix process and/or software functions available. (Im within Sonar, not using an external control surface). One of the things I may/may not understand is track mode locks controls to automation plot, clip mode doesn't, but uncertain relationship between clip automation plot, and control once a control is moved?
 
Anyway any comments or direction, and/or reference to automation use documentation would be appreciated.
 
Cheers