Overall I love this plugin. It is very useful and was one of the main reasons for joining WPMU.
I have one issue with this tool that could very easily be improved. Please update the preview shown on the page editor so that it only shows the maximum number of characters allowed and then truncates the rest of the title and/or description.
Another similar improvement would be to count the number of characters entered into the description and title fields as they were being typed. This would make life as an SEO much easier while typing in optimised page titles and meta descriptions without having to count the characters manually or use Excel. Something link [25/70] for example would be easy to understand (where 25 is the number of characters currently entered).
I look forward to hearing from you soon,