I'd only recommend HRM for people who haven't touched assembly before. For those that have, it is a bit of a waste of time and not very challenging...I kept hoping the problems would be harder, and maybe something that you wouldn't do in an introductory college course.
TIS and Shenzhen I/O on the other hand have unique challenges and are well worth your time investment for help thinking outside of the box. Many different ways to solve the problems, unlike HRM where there is basically one obvious speed and one obvious size solution.