I am delighted with Mellel as it fits my needs (research, teaching, academic writing) so well. The developer has been extremely responsive to questions and input for suggested improvements.
For example, about 6 weeks ago I wrote to both Mellel and Bookends developers and asked about the integration of the two. Redle immediately wrote back and said that it was in development and now here it is! Excellent addition of the Citations dialogue.
I love the integration of two-byte language capability and the ease with which you can modify character/paragraph styles. I used to use Nisus Classic, but this app for OSX is excellent.
This is a classic example of a Mac developer with a vision and the drive to improve that we all wish for in every application. The price is way more than reasonable. I'm obviously a devoted user and suggest you try this software.