You didn't mention why they are making this change. What do the three of you think will be different for you with the 640G.
The one feature of the 640G which makes it (currently) unique, in my opinion, is the ability to predictive basal suspend and resume when you are also using the CGM. However, the CGM does not necessarily work well for some people.
I use (an earlier version) of Medtronic's Enlite CGM and am mostly happy enough with it. But it tends to be finicky. It probably works well for me because I think I somewhat prefer things which are a tad finicky. Others hate/loath it. Still others have more of a hate/love relationship with both good and sometime bad results.
As for non CGM stuff ... well, I only think I know what I've read. The color screen and the volume control for alerts has been a long time coming and people are glad the 640G includes it. Some people think Medtronic does the menu possibly better than other pumps, but I really don't have an opinion. I am not sure about this, but the color screen may be harder to read in direct sunlight. It's a common problem with color screens on the currently available portable devices.