Reports and summaries
For some, this is one of the most important parts of the system.
TimeWarrior has a couple of report modes. The summary command option outputs a summary of total time taken on different tasks. There are quite a few options that can be applied to this, such as limiting the summary to a period or filtering by tag. It also has a graphical text-mode charting option. There is also an extension system that uses Python plugins for the ultimate in custom data processing.