There are so many factors that go into your ultimate bud yield...I've seen shitty harvests from friends using HID lighting. It's long been known that the most powerful lighting options commonly available are HPS and MH, but CFL's can definitely be used to grow a decent plant. I use CFL's exclusively for my clones/seedlings, and early vegetative growth. I like to use a mix of cool white and warm colored CFLs, to provide the widest spectrum I can. Sometimes, you just have to go with what best fits your growing situation- I live in an old house with sketchy wiring, and I can hook up a ton of CFL's, and position them all around my plants without worrying about burning my house down. I'd love HID lighting, but there's the issue of venting the heat in my small grow space. With CFL's, I only need a few small fans. My clones/seedlings under CFL's are doing great. You can help with the CFL issue of poor light penetration with techniques like SCROgging, lsting, etc. With more CFL bulbs, and careful growing technique, you can certainly grow decent buds with CFLs.