Apparently one's eyes are not designed to see blue light as well as other colours, particularly yellow. So a lamp with a very white light might appear, on paper, to be brighter than a much yellower light, which the eye perceives as brighter due to being set up to see the yellow light more vividly. Apparently this is true of blue boy-racer car headlamps where the light output is much greater when measured by a light meter but in reality, actual visibility is no better - or even worse!
There are some LED lamps which give a really nice light akin to halogen bulbs, a friend has some in his camper as direct replacements for halogen capsule bulbs but sadly they were a chance purchase off ebay and he does not remember where from. LED technology will get there, indeed, if one spends enough money it already is. ...almost.
Chris