Vision Plus make a difference to the brightness but so do the Blue Vision but to the same extent. I have Blus Vision now and have had tried Vision Plus. Blue Vision make the light WHITE not Blue and look really smart, where as the Vision Plus just look yellow and nasty
Vision Plus about 50% brighter
Blue Vision about 30% brighter
Dont get osram, ring, bosch and halfords none of them compare
(Brightness is also to do with the quality of your reflector in your headlight unit, sometimes the paint flakes off and leaves a matt back finish, CHECK your lights)