I wrote

Quote - (remember it's already SR1 of the 8th version of the software and it still can't render a simple room with Indirect Light. Is it still me who uses wrong settings all the time? Do you get better results with a reasonable render time?

I like to apologize for the first part Stewer. Yes Poser can render a room with IDL. The not so good front of the bed can be done better with more trials for sure. But does it really need to take 4 and a half hours (as for the posted render)? - maybe.
I did not know that inverse square should not be used on a point light in a setting like mine (it was the only setting I did not change during all those trials).

From the SM store site

Quote - Physically correct light attenuation for more accurate light falloff

Maybe they should have added "but should not be used above a night stand" :-)

Should I quit Poser? - no, it anyway was the wrong question. Should I quit Firefly? Not yet, maybe never.
New question: Should I try other apps to see what is possible (at what render times)? - Yes, definitely yes.

Last one: Should I like the render of johnpf (the bathroom) - yes, I do

Very last one: Is the community here one of the most important reasons I like to proceed using 3D software, even though I get so frustrated sometimes? Answer: The ultimate yes!