An Aussie technical mag did a recent article - it seems that the new 'LED Fluoro tube replacement' items - which fit in a standard (like the old 40 watt fluoro) fitting but need the ballast and starter removed - give reasonable usable light if the 'white' one is used, but the warnmer rated ones use different mixtures of the individual leds and also give lower lux output than the 'white' ones.