When it comes to marketing it is vital to be able to track how successful it is. You will want to be able to check improvements regularly with as little fuss as possible and the most importantly that they are accurate.
Finding good ranking software can be hard so you may need to take out a number of free trials and do some comprehensive research to find the right company. There are a number of different ones available all of which offer different functionality. Often the prices are based on packages such as number of keywords or number of websites to track. Some will allow you to white label reports and schedule them to email to your clients whilst others will require more manual work to get the report configured to send to your clients.
This is a must have tool for anyone who is serious about SEO and web marketing.