I have spoken with customer service at Weber and they have confirmed that there are three differences between the Q300 and the Q320. 1) the ignition system is different...piezo in the 300 and electronic in the 320. Per the rep I spoke with, the piezo is more reliable. 2) the actual cooking area is the same in both, but the specs include the warming rack which is standard on the 320, and which can be purchased later as an option for the 300. 3) there is a handle mounted LED light on the 320, and none on the 300. This is also available as an accessory for the 300. The rep I spoke with favored the Q300 because of the piezo ignition, and pointed out that if one wanted the warming rack or the light, that they could easily be added later.