Question on Yoder YS1320

Does any one out there own a Yoder YS1320? I current own a YS640 and I am thinking of upgrading. I am hoping to find some who owns who can give me some information on does it cook well does it hold temps better than the 640 and how does the heat management system work. My other choice at this point would be the FEC 100. Any feedback would great

Thanks