I am thinking of getting a new computer for my freelance work, I am thinking of getting Ryzen 1700X + RX 480 + 32GB RAM on 2000$ budget, I have heard that AMD has better Open CL support than nVidia. I am still a little new on how Houdini uses the hardware, I tweeted to companies who develop, Real Flow & Pf Track, they recommended getting a card with better Open CL support.
I am also into video editing and motion graphics, ( 2D stuff), so for that I have been using my 2011 Macbook Pro, Its given me a fairly good performance, and that's what I have been using to learn houdini, its given me a decent performance so far.
Macs were horrible for using Houdini 11 to 13, but since 14 I have seen it has become more stable on Macs, sadly Apple no longer makes computers.