The mysterious Widget: Great Tool or Landmine?

I think Widgets are a good thing but I'm not sure they are for an average Joe like me.  I'd like to use them on all my sites but the cautions are keeping me from it.  On my main website I have the ability to ad Widgets but on the same screen there is a big caution something like:  "Any support will have to come from the Widget maker"

Are there good Widgets and evil Widgets?  Good Widget makers and evil widget makers?

I'd appreciate hearing your experience and comments and would like to be pointed to a good Widget tutorial.