The current top of the line MBP has a Nvidia GeForce GT 750M with 2GB GDDR5 memory. It appears this is supported by looking here in the Mobile GPU section:

http://www.sidefx.com/index.php?option=com_content&task=view&id=2680&Itemid=390 [sidefx.com]

What is not clear to me is what degree of support this offers. Will it use OpenCL on the GPU? The MBP also has Iris Pro in it, does the software automatically detect the available GPU and use it? Elsewhere on the site, it is noted that Houdini does not work with multiple video cards, so I'm not sure about this.

for a serious work buy pc stick some entry level quadro in and buy as much ram as possible

Interesting, macs are not recommended for 3d work?

how about linux? i really prefer to avoid windows if possible.

I don't how well the GeForce GT 750M will perform, but if it supports OpenGL 3.3, Houdini should be able take full advantage of the card's capabilities.

Windows or Linux systems can accommodate a wide range of GPU hardware with fast, native OpenGL drivers. Because of OpenGL limitations in earlier versions of OS X, a Mac wasn't necessarily the most suitable choice for 3D processing. But the situation has improved [developer.apple.com] with OS X 10.9 and newer.

And now with Houdini 14, the viewport runs quickly and looks beautiful on all platforms.