Score Analyzer uses a grading system similar to most schools. A straight "A" means you are meeting your maximum level with a particular FICO measurement. Any "A" or "A-" are considered excellent ratings. Any "B+", "B", or "B-" signify acceptable grades, but there can be additional improvement in those sub-component of your credit report. "C+", "C", and "C-" are warning signs to identify areas of serious concerns. Any sub-components with a "C" are telling you that your scores are dropping from such concerns and need to be addressed. A "D+", "D" and "D-" are grades that indicate substantial concerns with an issue that are causing a significant drop to your scores. These issues must be immediately addressed to get you on the road to 850.
Just because you have a 700 or even 800 credit scores does not signify there are no concerns. A consumer with credit scores at those levels can still have areas in their report that are graded in the "C"s – where there are serious concerns. Additionally, any grades in the "B" level are acceptable. But, there is additional room for improvement within those areas.