With Rankwatch I can set parameters and get daily email notifications if certain keywords move up or down in ranking, by more than a set amount of positions that I specify. This is one of the few tools I've used that has been incredibly fast and accurate when it comes to tracking client keywords. You can set whether you want the keyword to be tracked locally, nationally, or in a certain area.
Easy to use with great dashboard! Review collected by and hosted on G2.com.
There have been a few bugs I have encountered, mostly related to entering in new clients or changing some location parameters (It had a hard time recognizing "St. Louis, MO". However, I've tweeted those to their dev team and they've let me know they are fixing them. Review collected by and hosted on G2.com.