One disadvantage to CFLs occurs when the electronics in the bulb fail long before the claimed life. The claimed savings in power consumption vs. bulb cost go out the window when the CFL fails prematurely.
In order to save a penny here and there, CFL builders (who are predominantly in China) would skimp on the circuit design and/or the components, resulting on bulbs that would fail long before their claimed lifetimes, due to heat, high average line voltages, and/or transients.
From my own experience, I think that the longevity has gotten better in recent years, however.
Yes, an occasional bulb will burn out early. But on average they last much longer than incandescent bulbs, and they use only about 25 or 30% as much power.
Also, we have a special situation in Vermont. The state subsidizes them, so they cost less than $1 apiece. I’m not a believer in subsidies, but as long as that’s the case—and I’m helping to pay for it with my taxes—I’d might as well take advantage of it.
But even before the subsidy, we were saving money over the long run.