I agree with him. There is something definitely lacking about the build quality of Samsung phones (I am talking about the S2, S3 and the Note 2-my main phone).
The way I see build quality, it is not about the size or shape of the phone (that is ergonomics). It is the tolerances, behavior of buttons, etc. For example the volume buttons on the Note 2 are a bit fiddly. The power button does not consistently spring back to the most extended position. The back cover does not fit flush with the phone. Even when closed, pressing in some areas produces squeaky sounds. The press-to-release mechanisms for the sim card and micros SD card are difficult to operate. Even the PS Vita and Nintendo 3DS have a better push to release mechanism. Small things, but they add up. Another good test I think would be to give two phones to someone who is not very into smart phones and ask them which is more expensive. Given a Note 2 and a Lumia 920, I know which one my mother is going to pick.