It depends on your needs and your willingness to be patience and learn your way throught the program. I mean, HM2 is a lot more user friendly so the learning curve is less steaped in comparison to PT4 as many of the reports are already preconfigured and cosmetic speaking is a lot more appealing than PT4 therefore is the software of choice by many cash game grinders specially since they can also use NteCaddy along side with it.
But PT4 is a lot more customizable than HM2 making the learning curve a lot steaper but once you get around it and get familiar with that the potential value of PT4 is a lot higher than HM2 since PT4 gives you the opportunity fo create your own statistics and customize your reports filters far better than on HM2. PT4 is mostly use by low/mid stakes MTTSNGs.
HM3 have been on beta testing for over 18 months now and its interface for many of its tabs is exactly like PT4, specially the HUD Editor part.
Im a official PT4 Premium Addon Developer so my comments might by biass but i do believe PT4 > HM2, cheers.