Octoboard also has an interesting pricing structure for its Rank Tracker—for example, you can track 50 keywords in your whole account but only 10 keywords for each client.
This structure means that if one of your clients needs to track more keywords than the others, you'll need to upgrade to a higher pricing plan. If you want your keywords to be updated daily, you'll also need to upgrade to a higher plan.
At AgencyAnalytics, we've been working on our Rank Tracker for over 10 years, and we never force our customers to allocate keywords to specific clients. We offer customers 4 different rankings for each keyword (Google, Google Maps, Google Mobile, and Bing), and we update it daily for all plans.