Quote - That depends on the quality you want.  Lux never ends, literally.  Technically, if you want a very bad render, it can be done in seconds.  However, most if not all renders will take more time than firefly; however, it will be much better quality than firefly in most cases.  The time it takes is up to you.  You can stop it at any time when it looks good enough for you.  One thing to keep in mind is that although the final render will take more time than firefly, you will probably get an idea about whether it is a keeper render well before firefly would finish.

 

Hope this makes sense!

What Jcleaver said!