There are lots and lots of different reports, and a number of ways to customize and parse and filter all of the data to find the statistics you're looking for. You can customize the categories and productivity level of any activity. You can also create your own categories, and enter your own activities (manually or with the API). The information is very accurate, and it is also possible to obtain the file names of the files you've been working on (in Word or Excel, for example).

I love the detailed reporting that RescueTime offers with regard to my computer and non-computer activities. It tracks everything I do from emails, to websites, to even what I do on my Android phone with the RescueTime Android app. It's very affordable for all the great features that you get. It helps you understand where your time goes and where you can make improvements.

RescueTime worked in the background and was able to quantify my time using different computer software.