This is a mostly superb extension that does exactly what it says it does with precision. Highlighting changes and being able to quickly filter what on a page you're tracking (as well as add granular conditions for the change) are invaluable.

There are a couple of things that could be better about its user interface (why does changing the delay on checking pages make me look at a block of code? why can't I pick colors for tags? why is clicking to view change history look so clunky?), but overall it gets the job done.