Broad spectrum bulbs (our standard option) include wavelengths from across the spectrum and emit a warm white light. Colour temperature of around 3500K.
Daylight spectrum bulbs mimic natural sunlight so colours are more true to life. They emit cool, blue-white light. Colour temperature of around 5400K.
Both types are equally effective so it all depends what kind of light you prefer. Broad spectrum bulbs are brightest and many people like the warm tone to the light but daylight spectrum bulbs work just as well because they have more blue wavelength light (just like natural daylight) which is thought to be especially effective.