Other problems of CFL

Compared to LED lamps, except for the most important point about CFL that it contains Mercury as mentioned in the last paragraph, there are also several important points that you should know about:

• They are less efficient than LEDs - CFLs, despite their efficiency, are still only about half as efficient than LEDs. A 10W LED downlight gives about the same amount of light as a 20W CFL downlight. 
• They have a shorter lifespan - The life of a CFL is significantly shorter if it is only turned on for a few minutes at a time: In the case of a 5-minute on/off cycle the lifespan of a CFL can be up to 85% shorter, reducing its lifespan to the level of an incandescent lamp. The US Energy Star program says to leave them on at least 15 minutes at a time to mitigate this problem. (LEDs can be cycled on and off with no problem and work better in cold temperatures.) 
• They have an undesirable form factor - CFL bulbs aren't exactly appealing to the eye and currently can't replace bi-pin halogen bulbs (MR16 and GU10) typically used in many track lighting applications. 
• Not Fully Dimmable - Dimmable CFL have emerged in the past year, but there have been reports of buzzing and color shifting while dimming as well as a limited range of dimmability. Most LED spotlight are not dimmable at the moment, but the ones that are, are fully dimmable and do not buzz. Keep a lookout for dimmable LED bulbs that we've found. 
• Warm Up Time - CFLs takes a perceptible time to achieve full brightness, and can take much longer in very cold temperatures. 

In one word, LED lamps are better replacement of traditionally incandescent lamps than CFL. Although LED lamps are a litter more expensive than CFL, but it will pay back by paying less to your electric bills. You also help to make our earth more green!