Difference between Cisco 7940/7940G (or 7960/7960G)?

What is the difference between the non-“G” and the “G” model of the Cisco IP Phones? They have 7940 and 7940G, as well as 7960 and 7960G phones. The “G” versions are more expensive… So far, the only differnce I can figure out is that the “G” versions have the industry standard version of PoE (Power over Ethernet), whereas the non-G has a Cisco proprietary version of PoE.

Are there other differences? If I’m not going to use PoE, is it ok to buy the non-G version?

Thanks!

The only difference i know is that one has icons and the other one has text printed.