They do. Even faster than incandescents.
If they are bright as soon as they come on rather than waiting for them to warm up...
They are. And you can dim them with a standard dimmer switch. (Although the color doesn't change to yellow/orange and they dim down like an incandescent lamp)
If they don't have a "hum" when they are on...
Less hum than some incandescents, no filament whipping around in it's own current induced magnetic field.
And the classic LEDs were rated for 100,000 hours (About ten years continuous use). Newer ones? 200,000 hours...
Thanks!