One of the most difficult techniques for me to learn in machine embroidery was to embroider with 
metallic thread.  There have been some very frustrating moments where I had to just walk away from it.  Over the years, thank goodness, I have learned.  The trick is to loosen your upper tension, slow the machine down, and put your thread on a stand or in a cup on the other side of the room.  Yes, you will still get some thread breaks but much less.
All of that said, I have fallen in love with gold work,silver work, and the look of a shimmering metallic design.  In fact, yesterday I made two black shams with gold metallic dragons.  Here are some pictures:
 
Remember when making shams, make them one or two inches smaller than the pillow insert in order for the insert to fill the sham to capacity for a better look and fit.
Have a great day.