I bought these bulbs to save energy and also because I like to use "Daylight" bulbs. Normally they give a more natural colour and are best for detailed hobby-work and for reading etc.
The bulbs are about avergae at warming up (so the delay is acceptable) but they do emit a rather cold colour - not like traditional daylight bulbs. Fine for a desklamp or "Anglepoise" but they didn't work well in ordinary lamps - far too cold a colour for comfort.
So, for close-up work, reading and perhaps sewing, great, but too cool for a room and not that bright either.