What is the difference between <input type="button" /> and <button></button>

Hi All

When i am coding with HTML, When a button is required based on my mood i
choose between  <input type="button" /> or <button></button> . I am yet to
find a reason to not use of one to another or at least a best practice of
using which one. So I would like to know from you all , which one you are
using and why ?

Also if possible please anyone explain what situation to use which one of
these and whether there is a possible performance hit dependencies and all.

Thanks & Regards
Nathasha
http://bestfragranceformen.com