The way I view Houdini is as an extremely power VFX tool that can handle massive data sets. Movies like San Andreas (the perfect movie for fluid simulation lovers) were done (I think) in Houdini and as such required data sets in the terabyte range. So to get the most out of Houdini, you need some pretty hefty hardware, if not a full render farm.
But if you don't have massive hardware, then is it fare to say Houdini is a bit over-kill for the average user. Kind on like putting drag racing wheels on a Volkswagen Beetle. In short, why go through that steep learning curve if you are hardware limited? Wouldn't C4D and X-Particles be a better choice?
Feel free to chime in ....if only to get this very interesting thread back on topic.
Dave