Nex-3 vs Nex-5

Pardon my ignorance, but what are the main differences between the Nex3 and Nex5?

I did a side-by-side comparison in dpreview and it seems the main difference is Nex5 having AVCHD video. Other spec are virtually the same, and yet Nex5 is almost $180 more expensive and having a more protruded hand-grip (an advantage for hand-holding but disadvantage for putting into a pocket).

Does the AVCHD feature justify the extra price and bullkiness?