This post is several years old, you would be better off reading the updated post on rank tracking software.
When working on a clients SEO project a purest might argue that the best metrics to measure performance are the number of keywords used to bring traffic to the site, the number of none brand terms for which you are listed or even something as bottom line as ROI, however, from a clients perspective you cannot get away from the classic “ranking report” or rather their desire to see it.
Clients like to know where they rank for what keyword and where they ranked for that keyword last month, it’s reassuring to see what raw metric is driving all of the others even if this is something the SEO industry is trying to distance itself from.
One long standing problem with “ranking reports” is that they are boring and visually unappealing unless you want to put some serious time into design or have some software automate the process for you. The problem with the software option is that when google changes the way it displays the SERP the software can fail and will require updating. Historically this has been a problem, enter Market Samurai (there has been no payment for this post and there are no affiliate payments made on sales).