It seems like a good option to be able to make them exempt, but I actually like the idea that membership can give their opinion about moderation, and just let me apologize profusely to anyone I've recently suspended.
One of the things I like about this sites interface over others has been:
a) the dark background / light text format which is easy on the eyes
b) post management: what's a response to what and has it been responded to.
b) the complete lack of gimmicks/noisy graphics.
Message rating doesn't tell me anything much because partisanship is usually a feature of the discussion sites I visit. I've only used the ignore function for kinds of posters who don't feature / continue in an annoying vein ... for long here.
A real boon would be one-click text formatting features built into the reply box. The need to write out dbcodes in 'longhand' being a bit of a drag in this day and age - especially in what is an otherwise slick-as-can-be user interface.
This is about the best one I've seen - you get to see formatting changes live on the reply screen rather than just seeing the formatting codes and having to preview in order to see what things will look like.