I was told this lights up immediately, and it sure does! It's in a three-bulb fixture, and I have to wait a second for the other two bulbs to come on. Plus there's no "warm up" time of dimmer light. They come in 2700K warm white light. There's a two year warranty, which I could have used on my other bulbs, and it has less than 1.5mg Mercury. I don't actually know how much the other ones have, but I understand this is significantly less. Correct me if I'm wrong! It comes in completely cardboard packaging, no nasty plastic to landfill, 99% recycled cardboard. No note on how much is post-consumer content. It also lists on the package a place to learn about dealing with spent bulbs, www.lamprecycle.org