I have previously tried the Cree 9.5-Watt Soft White LED Light Bulb, but was not exactly impressed. The bulb has an ugly dark spot on top and buzzes loudly when dimmed. Its EMI (electromagnetic interference) is so bad that it jams my garage door opener. Recently I found this new version Cree 11W 2700K A19 LED Bulb with 4Flow Filament Design) at my local HarDware store, and decided to give Cree another chance... [Physical Design] From the outside, this Cree 4FLOW bulb is shaped exactly like a traditional A19 incandescent bulb. The only visible difference is that it has several ventilation slits on both top and bottom of the plastic globe. Unlike most LED bulbs that rely on external heatsinks for cooling, this 4FLOW design has an internal heatsink with 4 thin fins inside the plastic globe. There are 8 LEDs mounted on those fins, and the heat they generated is carried away by air flowing through the globe (hence the name '4FLOW'). This is an ingenious design that cuts down the size and weight of the bulb. Even after hours of operation, both the globe and base of the bulb remain cool. On the other hand, there are some limitations that come with the 4FLOW design: - When the LEDs are on, the heatsink fins become noticeable from the outside. So the bulb looks like a peeled orange, instead of a smoothly lit globe. - The air-cooling effect works best with the bulb mounted vertically in an open-air light fixture. It does not work well if the bulb is mounted horizontally in an enclosed light fixture. - The LEDs are exposed to dust, bugs and other contaminants circulating in the air. So after a few years of use in open-air, I expect to find dirt accumulated inside the bulb, which will reduce its brightness and lifespan. [Power Consumption] I measured the power consumption of this '11W' LED bulb. It shows a steady 10W according to my P4460 Kill A Watt Electricity Usage Monitor. This gives a light efficacy of 815/10 = 81.5 lumens per watt. Interestingly, the previous Cree bulb is rated '9.5W', but consumes the same 10W in my test. So although on paper the previous bulb has a higher efficacy of 84.2 lm/W, in real life the new one is actually better. The power factor of the new bulb is a perfect PF=1.00, which is usually a sign of good electrical design, [Dimming Performance] I compared the dimming performance of 4 different 60W-equivalent A19 LED bulbs, connected to a TRIAC-controlled light fixture. - Cree 11W LED Light Bulb with 4FLOW (this product) - Cree 9.5-Watt Warm White (the old 'Black-Eyed Susan') - FEIT Electric 9.5W A19 LED Light Bulb - Philips 423491 11-watt 'Funnel' A19 LED bulb All 4 bulbs are able to operate from full to minimum power. The Philips bulb has the widest dynamic range, dimming down to a faint glow at minimum setting. The Cree 4FLOW actually has the worst dynamic range amount them. See my uploaded picture for their dimming performances. [Audible Noise] Sadly, the new Cree 4FLOW bulb still emits a buzzing sound when dimmed. It can be heard in a quiet room from 1-2 feet away. But at least this is a big improvement over the LOUD noise generated by the old Black-Eyed Susan. The FEIT and Philips bulbs also generate faint buzzing sound, but it can only be heard from a few inches away. [Electromagnetic Interference] There seems to be no effort made to reduce the radiation from this new bulb. It still causes strong interference when placed close to an AM radio. So I did not bother to test it in my garage door opener. [Bottom Line] The new Cree 4FLOW LED bulb is significantly better than the previous offering. Unfortunately, there are still plenty of rooms for improvements. As of right now, I have to recommend either the Philips 11W 'Funnel' or FEIT 9.5W LED bulbs over this product.