Well, for one, I see value in utilizing Kaspersky's cloud network. For two, WiseVector programmers have literally went out of their way to make sure it runs perfectly along-side Kaspersky real-time scanning.
Since there is no noticeable performance hit on my system and there are no compatibility issues between them, I just don't see any reason not to.
Edit: I did have to manually enter an exception for BCWipe in HitmanPro.Alert registry settings. Other than that, I'm really digging HMPA... the keyboard encryption is an added bonus.