I have more CFL's than you can shake a stick at and I've got to be honest with you, the light output ratio is at best 4:1, and for many of mine, it's more like 3:1. In other words, an 11w CFL puts out about as much as a good 40 watt bulb. My 15w CFL's are roughly comprable to my GE "Reveal" 60 watt bulbs... or not quite. Ended up using 17w CFL's in the room where I really wanted solid, bright light output that I previously had 60 watt Reveal's in. I have 14w globe style bulbs for both my bathrooms and they are MUCH brighter than the 35w and 40w bulbs they replaced.

Pretty much all the ones I have are 5000-5500K since I hate yellow light. Most all the important ones are fast-start too - light output within a tenth or two of a second of hitting the switch. The lesser important ones are the old style CFL's that take a second or so before they come on, but I can live with it. I keep saying I need to write up a review some day of all the bulbs I've tried. I think I've sampled at least 8 different varieties of CFL's by now and they really are all different! Different shapes, sizes, quality of light, time delay to light output, percentage of usable light in the first few seconds after start, and so on.