Cons: Delayed brightness.
Like most fluorescent bulbs it takes a few seconds to gain full brightness. It's nice in the morning, that's about the only time. Great value and decent life span. I think this light bulb is the way to go right now for all around value and Eco-friendliness.
I did have one fresh out of the box that blew instantly. I used about 12 more and it wasn't an issue for any of the others.
Recommended as a preferred green partner by greenprintsinc.com.