In order to compare the films, you have to develop them to the same contrast index, preferably of the same scene. It takes a lot more than one roll of each to decide any real difference.
Since HP5+ is naturally a little bit lower in contrast than Tri-X, you have to adjust developing time, agitation and so on to compensate for that. YOU control the final contrast of the negative; it's a matter of working with your materials until you have the results you need. Get the final negative contrast the same in both films, and you will have a much better idea of what each film does, both from a tonality and grain standpoint. Print the negatives, at the same contrast grade. Adjust film developing time until both types of film print with similar contrast on the same paper.