Cree has started selling their third generation of consumer LED bulbs, called "4flow". I haven't seen them in person yet, but they seem like a pretty crazy departure from the old design.
While the old design used a metal heatsink to keep the LED elements cool, the new design apparently relies on convection - air flows through the slots near the bottom of the bulb, over the LED elements, and out the top.
But it seems to me that this design is only effective in a vertical configuration. And indeed, all the Cree marketing materials I've seen show the new bulbs in an up-and-down orientation. A lot of our light fixtures (the majority, now that I think about it) have the bulbs in a horizontal arrangement, or in the case of the ceiling fans, at a 45 degree angle.
But apparently the new design allowed Cree to cut the retail price by twenty percent, which is no small feat.
So, I don't know. The guys at Cree seem pretty smart, but I'm not buying any of these new ones until I hear some real-life reviews after several months of use.
The good news: Home Depot has cut the price of the old bulbs by thirty percent, presumably to clear out stock before the new bulbs arrive. So I picked up three more bulbs when I was at Home Depot today. I'm slowly clearing the old, smoke-stained, mercury-based CFLs out of my house. In fact, I think there are only nine CFLs left in the house's built-in light fixtures :-)