I have both the glass nebulizer & ultrasonic (atomizer) diffusers, and here's my take:
I like the atomizer better because it's VERY quiet, uses water which gives a little humidifier effect, and you can diffuse ANY EO in it - even the really think ones. Because the atomoizer breaks down the oil into smaller particles than the nebulizer, the EO will hang in the air longer. I love mine - I liked the glass nebulizer too, but mine was loud. And my atomizer has timers and diffusing levels, which I LOVE.