I have Vue also, as I mentioned before and most of my renders are done there.  However I do need to mention that Lux has a big advantage for me, anyway.  Although the renders can take a long time, the renderer plays nice with windows so I can be busy doing other things and not have the PC act like it's filled with mud, as what happens with Vue sometimes.  Also, in some scenes I find it faster in Lux than Vue.  I expect that will change more towards Lux's favor once GPU utilization is added.   Expected to be the next version, btw. 

However, there is a lot that Lux can't touch, that Vue handles well.

Lux handles architectural renderings extremely well.  Organics, not so much.  Landscapes are OK.  Vue handles all of these well.  Lux only seemely beats it in Architecture, but not by much.

OTOH, Lux is cheap.