I haven't used the Commuter but the Symmetry fits. Thus far I've bought a Speck, a Symmetry, and an Incipio case and they all fit my new iPhone 6s Plus.
Sent from my GORGEOUS, SEXY, AWESOME Rose Gold 128G iPhone 6s Plus ️️️
Well feck it, looks like the one for the 6 is different. Got one delivered and the part number is different . I won't know until my 6s arrives but i doubt it will fit.