I don't understand why render time is such a big worry for people?

Render quality should be of primary importance. Superfly can produce renders far superior to anything that ever came out of Firefly. It's an unbiased renderer so naturally those results are going to take longer, especially when you include things like refraction/caustics, strand based hair, etc. Superfly isn't "slow", it's just that Poser users have gotten used to using heavily biased renderers. People had the same complaints when Firefly came out, even though it was light years ahead of the P4 renderer.

Your typical workflow should be:

Create a small preview size, Render Dimensions: Fit in Preview Window, turn on Render Settings: Progressive Refinement and use that to do some quick preview renders of your lighting/scene.

If your preview looks good, zoom in and doublecheck areas like eyes, etc with Render: Area Render, rendering only that small area.

When everything looks good, crank up the render dimensions, increase the samples and let it render while you go do something else. If it's a complex render go watch a movie, or let it run overnight while you sleep.