A quick update:
The newer dewalt DCB120 batteries are now 1.5ah and have the same cells (I think?) as the milwaukee red lithium/ridgid hyper (see pics).
You can easily tell the new batteries from the old; the newer batteries have 1.5AH on the side battery labels now and the front of the batter has a yellow background with black dewalt logo.
As for the cells, I couldn't find info on them but they look identical to the milwaukee red lithium cells except for a slight difference in the model numbers. Milwaukee uses the samsung INR18650-15M while the dewalt uses samsung INR18650-15B.
Either way, I'm extremely satisfied with the dewalt 12 volt max tools I have (flashlight, drill/driver and screwdriver with the impact coming soon). I appreciate that dewalt is using some good cells in their batteries.
Pics: