Wow, had never heard of the Simply 16. Must be brand new. The HQ site has this comparison chart of machines:
http://www.handiquilter.com/machine/comparison/
Handi Quilter has a pretty good reputation, but I know nothing about the Simply 16. Do examine the frame to see how sturdy it is. You want poles that don't bend. I know that some of the Grace frames have wooden poles that tend to bend in the middle; don't know what HQ frames are like.