I am a long time 3ds max user using Houdini to extend my procedural modeling toolset. But Importing and exporting from 3ds max to Houdini and vice versa is not flexible. It also disrupts the procedural and workflow both applications. I know there is a Maya plugin for the Houdini engine. (You can even be check to auto install it during Houdini installation). It seems to support more features than the 3ds max version and be updated regularly.
There is also a 3ds max plugin of the Houdini engine. However it does not seem to be actively developed. A lot of features seem missing. Intergration should be flexible into the 3ds max modifier stack. No plugin compilations or fast updates for newer 3ds max versions like 2018.
Good Houdini engine integration into 3ds max, would attract a lot of 3ds max users to Houdini. (Especially for modeling purposes, not only FX). I would love to be able to create procedural models/tools in Houdini and use it in 3dsmax as part of my modeling pipeline. For example someone created this soft blended Boolean HDA that works in Maya but not in 3ds max: https://vimeo.com/211722563 [vimeo.com]