First of all, this is one of the best search-related plugins out there, IMO.
I've noticed an issue with it, though:
On my search page, besides the search results, I have links to some other posts (in the header).
The problem is that the box that says "You arrived here after searching for the following phrase: ..." is displayed for those posts, also, even when there were no search results.
The plugin should show the box only if the user clicks on one of the search results.