I'm interested in what better features it has?

For me rendering products in controlled environments, Maxwell render, an unbiased CPU only renderer, would take too long for me for production quality renders. I suppose Maxwell Fire is a bit faster but I doubt if Maxwell Fire can keep up with KeyShot or render as high quality as Maxwell Render.

I recently just tested Octane with my workflow (and I have both the Nvidia 1080 and 980ti installed), and I don't think it will work for my workflow. While renders are a snap (even faster than KeyShot on my rig), scene setup is too long. In KeyShot I can very quickly create 'render sets' where there are different positions of objects, with different materials, which I can then render at 4K resolution in a snap. I literally go to lunch and finish a dozen renders, each with different lighting, materials, camera settings and component configurations. The workflow for setting something like that up in Octane would be a deal killer for me-- and I would think the same could be said for Maxwell Studio as HyperShot uses a siimilar render engine.

If I recall correctly, HDR Light Studio has a fairly restrictive policy on creating Light Maps and in particular won't allow you to resell them. Not sure if that's a problem, but might be worth looking up. FWIW, KeyShot has a proprietary HDR format of it's own with their HDR Studio which sucks, but I've been told by their CEO they will be opening it up to export non proprietary formats soon. I hope that's the case.

Were you able to do any performance testing in any of these solutions? (Maxwell, Thea and Arion)