I personally don't like the new version of HM. (HM3) so between the two I prefer PT4. In the end, it is a matter of taste since the two fulfill their role well. However, there are some newer softwares like Hand2note that are worth giving a try.
There are different kinds of poker software. You can not compare HM3 or PT4 to flopzilla, icmizer or pio solver as all of these have different functions. What most people use is software which serves as HUD and also as database with your history of the games and hands you play and money you win. HM3 and PT4 are of these type. I use HM3 and it works good for me. Some people prefer PT4. You will not make mistake with any of these two.