Mike,

When picking a render program, I'd look at the total time involved in the workflow, not just the render time.

For example, Octane with a good GPU card is fast, but it has a very long learning curve. Lots of controls to noodle with to tweak your final result. IMHO - a long set-up time.

KeyShot is both fast to set up, and fast to render. But at a higher start up cost.

Maxwell, IMHO is somewhere between the two above.

So I would decide where you see yourself in 1, 3 or 5 years. My guess is, since you've mastered MoI, you'll be into 3D modeling professionally soon.

And if that's the case, you may be money ahead in the long run to put your learning curve into a package that will allow you to under-bid your competition.

That may mean investing in a more expensive package at the front end to make more in the long run.

Also, decide what type of rendering you'll most likely concentrate on. Some professionals specialize in just one area: architecture, cars, medical equipment, consumer products, packaging, jewelry, advertisement, etc. Look at the gallery's for the various render programs and you can pretty well determine which specialty groups favor which program.

Ed