Here is a picture where I replaced the UALP around the camera with a spot light that is at the same location and pointed in the same direction as the camera (something you cannot do with physical lights and cameras). I used the same slightly pink color and 50% intensity. There is no UE2 ambient light in here, so it should be compared with the image above before I added UE2 ambient.
The main difference I see is the spot light has blown out the walls, especially behind V5’s head. The spot light has no falloff ends feature, so you cannot limit the illumination of the walls behind. The extra control of the UALP however comes at a price. The render time on this image with the spot light was only 1m 33s compared to 5m 50s with the UALP. (Note I may have cranked the samples up higher than needed on the UALP. I had it at 64.)