Actually, delay 2 would probably do a better job as an area light for big rooms, as long as you keep it away from any surfaces. At equal "light" values, delay 5 doesn't have anywhere near the reach of delay 2.
Delay 5 is my choice for the best all around light, but I have to bump the brightness up to around double of what would look okay with the stock delay lights.
The bad side is that delay 5 suffers from not having much of a "hot spot" near the actual source. When using it for obvious point sources (such as light3_8) I often have to add a second light, with high brightness and high wait, just for the "hot spot".
What would be nearly perfect is a delay that was a mix of 2 and 5, with a center hot spot closer to delay 2 but with falloff like delay 5.