The default conversion of specular materials in Octane is too high. Change the index to 1.3 for a less shiny result. The default 0 setting is a left over from the old version of Octane when speculars were handled differently

Using default settings to compare render engines is a bit tricky since most settings depend on the scene being rendered (lights intensity. emitter meshes, reflections, volumetrics, etc). The default high quality setting for firefly is pretty slow and often completely over the top. I almost never have a FF render which takes longer as an hour - with the same spu power you have. The FF Rendersettings script from Dimension3D allows you to reduce the IDL cache and IDL bounces independent of the irradiance cache. Optimizing those will dramatically reduce your render time.

I use both Firefly and Octane. Firefly's ability to tweak materaials is pretty good and much easier as in some other render engines. If it was an unbiased render engine and GPU support it would be awesome.

Octane is a great render engine and v2 has now added a lot of very useful features. One advantage of Octane is that the speed is linear to the number of GPUs and you can add more (if you have the space and money) and if you want more speed you can go to network rendering as well - all the additional network node are  now like new GPU cores.