When you look at the life span they are a great value and think of the space you'll save, because they last over ten times as long a "double life" bulb. We are using them in my home and give off the same light that our old General Electrics give. After shipping they are about $1.25 a piece but with a 25,000 hour life span, you'll be throwing away the lamp before the bulb goes bad.
I like saving money and I like seeing, so we use a mix of bulbs in our house. For general lighting we use CFLs. For reading and detail work (shaving), we use incandescent bulbs
The 10-year 100-W bulbs last that long because they run cooler, which means they put out only 1060 lumens (about the same as a 75-W bulb). Regular 100-W bulbs put out about 1600 lumens. They are double-life, but 2/3 light.
But they do same money if you are OK with dimmer bulbs.