I have been anxiously awaiting the arrival of my Evolux S (I got the warm white model). Even if LEDs are relatively older technology, I'm excited by the new momentum they're getting and all the new applications. The bulb doesn't disappoint in that way - it's relatively futuristic looking and a lot bigger than I was expecting.

I did a comparison with the CFL that I've been using for the last several months by putting the Evolux in my bedside lamp. The quality of the light is fantastic. Similar brightness to the CFL, but warmer and easier on the eyes. It's totally sufficient to read by.

The only downside is there is an audible hum that emanates from the bulb. I don't know if it's the AC to DC transformer or what and the sound is incredibly easy to ignore, but it still warrants mentioning. If the bulb were higher up (like recessed ceiling lighting), I don't think this would be an issue at all.

Also, I have yet to challenge the 50,000 hour life in my first week with the bulb, but I'll keep at it....

When I first took out the CFL from my bedside lamp and put in the EvoLux S, I literally exclaimed "Wow, that's bright!"  Yep, out loud.  I’ve had mine for about a week - and yes.  It is bright. 

Doing the touch test, an incandescent in my lamp got hot within 5 minutes of having the lamp on. The CFL I was replacing warmed within about 7 minutes. The LED? Even after having it on for an hour, I could put my hand on it and it was cool.

I can't speak quite yet to the long term cost savings...but given bobkart's formula, it looks like the EvoLux S will cost about $3.22 per megalumen-hour in comparison to a 100-watt incandescent which would cost about $11.04 per megalumen-hour.

The only drawbacks of note that I’ve experienced are:

a) light diffusion - The light is not as diffuse as an incandescent or CFL (which I think is why it caught me offguard that first flip of the on-switch...because basically I was standing over the open top part of my lamp shade and a ton of light came up at me).   I think the bulb would be a little better suited in an overhead downlight rather than in a bedside table lamp.  That's next on the list to test out.

b) you can hear the fan. It’s pretty quiet. But if you’re reading by it, you can hear it hum.

Overall, it’s a great option for a bright LED light bulb that’s available now.

I have the Cool White version of this LED lamp (I don't care for the Warm White color).

The brightness is fine, one of the few LED lamps I own that is this bright (900 lumens).  It is also better dispersed than most LED lamps.  But the CFL I replaced with this was in a fixture above head level with the top of the bulb pointed upward, and even though this lamp is brighter, the CFL gave more light downwards, due to the fact that very little light shines downard (below a horizontal plane) from this LED lamp.  So this lamp would be better for applications in which it is pointed downward if the lamp is overhead, unless lighting mostly just the ceiling is sufficient.  Lastly, the fan is not quite silent although it is very quiet.

All in all a decent value considering price/brightness/efficiency/lifetime, you just have to consider the fit with your application closely (as with any replacement LED lamp).