as mentioned by myself and many others in this thread ease of use is still c4ds main strength. it seems to be particularly popular among designers and generalists, also people who usually don't have that much of a technical mindset. as for myself i've learned to like the technical aspect of things through learning c4d, and only because of that i have the perspective of being able to flirt with houdini. if it wasn't for c4d, i'd be scared sh*tless even looking at it. what makes c4d still worth every penny for me is that i'm able to produce stuff very quickly, so the money i make by using it doesn't remotely compare to it's price. so at least to me c4d is still a very good deal, although i'd also like them to step up their game. i don't do much vfx stuff for work, or have the need to incorporate the most fancy procedural eyecandy imaginable to the stuff i usually do. sometimes a little bit more funcionality would be nice, but i can usually get by with a plugin or another idea to solve the issue. even though i'm not that happy with c4ds pace of development these days, i'm still happy to use it every day. i believe houdini can be a huge time saver for complex stuff, but for the simple things c4d is still unbeatable in productivity IMO. so right now i don't think houdini is that much of a threat to c4d, even though a lot of c4d users have picked it up, i believe most of them still use c4d for the simple day to day work. for me it isn't an either or kind of question, i see houdini as an addition to my toolset, not really a replacement. if houdini ever manages to get near the ease of use of c4d it will be a threat, for now it's more like apples and oranges. others with a more technical mindset and more sophisticated needs might see it differently, but the fact that c4ds userbase is still growing tells me there's still a place for it.