The sebson are very bright, but it's more of a cool white as a warm white. They are quite warm and surrfen (operated as probably any LED you would like dimmed). At maximum brightness it is not buzzing. If one dims very far down, they flicker.
Currently, I'd rather recommend the "LE 10 Watt Dimmable A60 E27". These LEDs hum / buzz also, however, have a very pleasant warm white.