Thanks for the comments everyone!
I definitely want to see if I can sit behind either machine and play a bit to inform my decisions. The Juki dealer in my area is brand new and doesn't have many models in yet, but I'm hoping to get them to stock the HZL-110. The Janome dealer in my area is tiny and run by a slightly gruff older man. I went and talked to him one day about machines, and he never offered to let me try one before buying, but I guess I didn't ask.
Just to expand the conversation a little, are there any other models in the $300-$600 range that anyone would recommend?