Does anyone have any experience with v-ray in Houdini? I'm interested in how it compares to Arnold mainly: render times/quality ratio in complex lighting scenarios and "hard to solve" shaders (skin, hair), but how well it's integrated too. The former comparison could be found somewhere else I guess since it's program independent, however, some things could differ based on the latter issue (integration).

I am using Vray for Houdini at the moment. It is quite good. Basically, it is the same Vray in the other 3D packages but integrated for Houdini. I found Renderman and Octane are faster than Vray, but quality in Vray is impressive and truly easy to use. I like UV randomizer option it saved me a lot of time and this option alone kept me away from Redshift.

You might want to try it before buy. I think Vray for Houdini will get imprved overtime. I am having issue at the moment with Vray Fur SOP node and Vray Proxy keeps crashing Houdini. But other than that, it is a decent renderer with great payment options (Monthly/Annually) that fits everybone pocket.