A few days after I wrote about Sequel Pro, a link from Daring Fireball leads me to Querious, a commercial MySQL management tool. At a glance it seems to offer everything that Sequel Pro has, along with the ability to manage users and permissions.
Hot on the heals of this The Apple Blog has a Sequel Pro vs. Querious showdown. The conclusion is similar, and the comments make for interesting reading with links to further tools.