Obviuosly it is not a decision someone can make for you so I guess it is best to give you some information and let you decide.  For a start the lights in Lux are very different from Poser in that they emulate the light of the real world.  If you come from a photography background you may find that lighting in Luxrender suits you, others will may not take to it so easily.

Lux takes a long time to render but on the plus side you can make some lighting and film response changes on the fly and see them reflected as Lux renders.  Again this is built around photography with changes being made to apetures and film speed as well as lights.  One feature I really do love is the ability to suspend a render and start it days or weeks later from where it left off.  This is useful in the sense that the render is never finished in the Firefly sense and you stop at the point you are happy with it.

The problem I have with Reality is that, while it makes a very good job of guessing the material or texture from Poser figures and props, it is limited.  Lux has the ablilty to create some stunning textures but it is by no means simple and porting a scene from Poser to Lux, even with Reality, can take a fair amount of time. 

Having purchased Reality I do use it for some special renders but a good 90% of my renders are still done in Poser.

That's my personal experience for what it is worth but I hope others who have used it far more will chip in so that can get a balanced view before you let go of your cash.

 

 

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.