The Coronet is a rebadged HQ Simply Sixteen. The Gallant is a rebadged HQ Moxie. The Gallant would be a current production machine while the Coronet is discontinued.
Having driven the HQ version of both as well as all of the APQS machines and owning a HQ Amara only because the Lenni's table wouldn't fit in my space, I'd encourage you to either attend an APQS roadshow to get roadshow pricing (or watch for demo Lenni units on the APQS website) OR purchase the HQ version of the machines in question IF you have a decent Handi Quilter dealer in your area.
If the new APQS table allows a Lenni to fit in my space, I'm planning on switching. APQS machines are the smoothest, easiest, silkiest I've tried, especially the Lenni.