Regarding midrange, upper end, and imaging, you get more, dollar for dollar with a book shelf than you do with a floor stander. With the book shelf, you aren't paying for the extra cabinet that goes to the floor, or the design of the bass portion of the speaker.
If you value imaging far more than bass response, I would definitely audition book shelf speakers before floor standers.
If you value imaging far more than bass response, I would definitely audition book shelf speakers before floor standers.