I have put a couple of renders in my gallery and in another thread mustang2011 pointed at images in his gallery.  I think he uses reality 2 with Daz Studio but it will give you some idea of what Luxrender can do and worth a look.  I was impressed with what I saw there.

The downside of speed always comes up, what does not get the same coverage is the fact you can suspend a render and resume from that point days later and you can change the things like the tone mapping and and colour temperature during the render, so it is a question of swings and roundabouts.  Trying to work out if Firefly or Luxrender is better is a pointless execise it depends on the user but Luxrender is worth playing with in my opinion.

 

The only other suggestion I would make is use the non-OpenCL version of Luxrender, at least at the start.  My videocard supports OpenCL but the driver must be flaky as my machine 'Bluescreens' when I use it.  That said from what I remeber of your build you had a high spec pro graphics card so you may not have the issue and if it is stable it should shorten your render times.

 

 

I use Poser 13 on Windows 11 - For Scene set up I use a Geekcom A5 -  Ryzen 9 5900HX, with 64 gig ram and 3 TB  storage, mini PC with final rendering done on normal sized desktop using an AMD Ryzen Threadipper 1950X CPU, Corsair Hydro H100i CPU cooler, 3XS EVGA GTX 1080i SC with 11g Ram, 4 X 16gig Corsair DDR4 Ram and a Corsair RM 100 PSU .   The desktop is in a remote location with rendering done via Queue Manager which gives me a clearer desktop and quieter computer room.