I hate to be one of these people, but there are plenty of threads like this about the pros and cons about rooting. Please search....
Just by typing in the word 'rooting' these results popped up immediately.
http://androidforums.com/sprint-htc-hero/38911-guide-root-rom-faq-tutorial.html
http://androidforums.com/how-tips/39176-rooting-my-droid.html
Please use the search feature, this forum is getting clunky with multiple threads containing the same content.