After the disappointment with the Roto Weeder, I was a little reluctant to try another product.  I'm writing this a year later to tell everyone about Grandpa's Weeder.  This thing is very well made.  It's heavy cast metal with a nice wood handle.  It works by situating the two forked prongs over the center of the weed and stepping down on a metal bar.  You then push or pull the wooden handle in the direction of the bar.  This closes the prongs, and you pull up the weed.  If you get the prongs centered, it will pull up even long taproots.  It does a fair job on grassy weeds, too.  I just love the thing.  The lever action of the bar and handle doesn't strain the tool at all, and it should last forever.  Woot woot!