Another problem I have encountered with CFL is they will not fit in all fixtures. With the large diameter just above the base, they will not screw down far enough into the fixture to make electrical contact
I had the same problem with my pot lights, had to buy a socket extension, not sure how much money I am saving with the cost of the cfl bulbs, socket extensions, and loss of heat.
Interesting thought, I use heat 8 months of the year, regular bulbs generate heat, CFL's do not, so I now have to replace that heat from another source, electric heat, or propane furnace.