Just found time to make a little interior archviz Bench comparison between Luxcore 2.4 and Cycles 2.82a.
The test scene was made artificially hard to put pression on both engine. For example the high bounces set of 24 for all path (diffuse/glossy/transmission aka specular). Also the narrow window help to stress both engine radically diferent approach to sky portal (cycles use portal vial manually placed area lamp while Luxcore do it automatically by detecting all opening area of the scene).
At the end apart from the left white shelves where cycles is cleaner Luxcore is way cleaner in all over place (walls / under table & chair / windows area). Luxcore also look more realistic and brighter thanks to its integrated caching engine.
Finally in this test Luxcore show a striking 4X faster render while being nicer.
Note that this still feature light traced caustics so it is even brighter than the video one.
Youtube video :