been using houdini quite a bit at work, still not very good at it though, does take a while to learn it, but it seems like a very powerful too, although missing some of the nice pre-made tools in 3ds max or maya, houdini makes it up by letting you create your own tools easily inside the software itself. and it seems like all the studios are jumping on the bandwagon that is houdini, everyone is looking for houdini fx TDs. Might be a good software to invest some time into and learn.
and you can learn a lot from here: http://vimeo.com/user2030228
have fun houdini-ing!