Used it a couple of times so far. Does what you expect, type the regex and it highlights the matches on the page, pressing Enter repeatedly jumps to each successive match.

It would be nice after pressing Ctrl-Shift-F to have focus go to the search box. Like that Ctrl-Shift-F is a toggle which returns focus to where you were.

Love being able to use regular expressions in on page searches. Needs a few more usability things as mentioned in this and other review to get 5 stars (at least from me). Good job. Thanks!