Reviving this topic as I'm starting to look at alternatives to Bunkspeed/Visualize. While that engine has been my preference for a few years it definitely has its limitations, the largest of which being a very homogenous look to most of the renders you get out of it. Until you really dig into and tweak a scene most materials are extremely plastic-y, and it has a habit of rendering soft shadows as large blobs of grey (similar to something you would create in Photoshop with a heavy gaussian blur.) I'm also less than stoked on Dassault axing the entirety of the Bunkspeed materials, support, and forum archives, which were really helpful.
The most useful features I've found from Bunkspeed, and what have kept me running a legacy version post-Dassault buyout, are GPU rendering (both real-time and final image) and the ability to queue up multiple renders to process all at once, rather than setting up and rendering each image separately. If there's something out there with these features and potentially better quality, I'd be willing to take a look.