There also was an article comparing them lately, btw:
"Le sprint de Cornet et Simon
The main points were: both from Nice and current French number 2, with a possible shot at the number 1 spot, unexpected raise in the rankings this year based on a huge confidence and a stable relationship with their respective coach, same straightforward style and open relationship with the media (in opposition to the two French number 1 who always seem defensive towards the media) - and also the fact that they both still lack a good result in a Slam.
I found the comparison pretty far-fetched, they seem very different to me - Alizé is so much younger, had a very sudden raise in the rankings, she's much bigger in the (tennis-related) media, etc. But some points are true, especially the stability and the attitude with the media imo.