O.K., for those who want a quick answer, I boxed up my pair of R1 Evo CS's to return to Amazon.
For a more complete explanation:
1) We currently use standard Sena R1 helmets;
2) We don't do group rides or anything, just my wife and I riding together;
3) We like to be able to talk to each other during some parts of the ride, and listen to the FM radio on other parts;
4) We do not have the helmets paired to any phones, and do not wish to be able to answer calls or talk on the phone while riding.
As such, we have now found that the standard R1's do just fine for us.
Based on 2 rides with the R1 Evo CS's:
We did not notice a significant (or really any) better sound fidelity from the strap speakers on the CS helmets as compared to those mounted up in the foam of the standard R1's.
The 'mesh intercom' on the CS's was quieter during pauses in speaking as compared to the std R1's.
The voice command functions of the CS's were of little benefit while riding. I would say that most (75%) of my commands were understood and the helmet took the correct action. For my wife the percentage of successful voice commands was maybe more like 20%. If we had kept these helmets we would have turned the voice commands off in the configuration menu.
Probably the worst difference between the 2 helmet types was the intercom vs the mesh intercom. I found the intercom on the std R1 to be stronger, clearer and have fewer break-ups and crackling during use. We did not find the mesh intercom's connection to be more stable, per Sena's marketing.
It took longer for the CS's to boot up (nit pick gripe).
Our biggest complaint regarding the intercom differences maybe relates to how we use our helmets. With the std R1's, we both start up our helmets, and both turn on the FM radio. Then with a tap of the center button, the radio is cut off and the intercom is opened on both helmets. Another tap of the center button (by either rider) and the intercom shuts off, and the radio comes back on in both helmets. So either rider, at any time, could open up the intercom and speak to the other. Then either rider could close the intercom and both riders could listen to their radios.
On the CS helmets, I did not find the mesh intercom to work the same way as the standard, and could not determine how to make it work the same way per the manual. The center button control turned the mesh intercom on or off. It did not 'toggle' between intercom and FM radio, like on the standard R1's. As such, if both riders were listening to the FM radio (mesh intercom would need to be 'off' on both helmets) and one rider wanted to speak to the other, both riders would have to turn their mesh intercoms back on. Not possible to do for quick communication ("glass in bike path"), or if the riders couldn't clearly see each other. And sometimes my wife and I may be separated by 1/4 mile or more.
Due to this intercom 'issue', the new Evo CS helmets were not as useful to us as our old std R1's, so they got sent back.
The mesh intercom might be of great benefit to larger groups of riders, especially if for example a lead rider needed to give different directions to different groups on the ride. But that is just not our use case, so the more complicated Evo helmets actually worked worse for us.
Now to find and buy some Sena visors for our std R1's. I see that Sena supposedly has the medium sized ones in stock, but no large.