cloudy days vs CFLs

i have a few seedlings that im keeping at home until they are big enough to be planted. my question is, for a seedling which is a better light source: a few daylight CFLs or leaving them outside on a cloudy day? ive read that the sun will have more power than any light bulb can make even on cloudy days, but i was thinking that since the CFLs are very close to the plant the intensity of light might be stronger? i noticed the seedlings looked like the had stretched more than usual after a couple cloudy days, but when i have grown seedlings under CFLs they are always very short and the leaves are closely spaced. thoughts?

I have heard that too because sunlight has more visable light than artifical lights can hope to produce. Take a cfl and put it outside during a cloudy day if you cant create shadows then the sunlight is more powerful.