My experiences: First off, although I've owned and used Poser, Carrara, Bryce, (even Animation Master) for years, I'm more a casual user than anything else [read: perpetual newbie] to rendering.

However, I have a specific look in mind and I won't give up until I get it. And I think I've almost found it... using Poser 9+Lux, using Reality.  I have a very high polygon face + hair setup.  At least in Poser, it looks very wrong no matter how I play with settings. And at 1280x1280, Poser 9 just stops/aborts rendering with a partial-hair frame and a subscattered face. Anything less size still looks bad for materials.  To be fair, I'm probably doing it wrong.

However, the same setup is unbelievably real in Lux. Sure, a 1280x1280 takes 5 hours to get to 200 samples per pixel (my base minimum), and 50 hours to get to 10k (wonderful). [Machine: i7(dual)-win8-16gb and a terrible graphics card (NVIDIA 640) plus one slave (i5)].

This has inspired me to go deeper. LuxRender's CURRENT GPU set up (1.2.1), I've found, is broken - causing bad white spotch looks (perhaps it's NVIDIA vs ATI on OpenCL). If you have a bad image, try turning off GPU [for now]. Version 1.3 (within a month or two) has much better GPU (and has daily to weekly pre-stable downloads to use now).

I tried a NVIDIA 660ti and, with the drivers bombing with Lux, read that (supposedly) NVIDIA cripples (or doesn't fix/doesn't improve) their drivers regarding OpenCL. All I know is, I installed everything (even the partially hidden OpenCL drivers available on NVIDIA's site) and their card still doesn't work / drivers bomb.

Soon, I'll be trying an ATI RADEON 7970. 

Bottom line is, I see the best reality in Lux and with Lux continually improving their engine, including GPU, I'd rather put my resources in hardware and have multiple rendering engines to choose from. Reality does an EXCELLENT job of bridging Poser to Lux.