, PopeDai wrote

I understand the 928 is a derivative from the 920 as something for non-GSM carriers.

Yep, essentially a 920 +CDMA and a few other tweaks, including an AMOLED display and Xenon flash.

Good comparison photos on the following page.

http://www.wpcentral.com/nokia-lumia-928-lumia-920-better-and-verizon

It is actually a different size & weight to the 920, but otherwise much the same.