Mars is one of the earlier shoujo series I read, and it's one of the earlier shoujo series to be brought over to the US in translation. This was my first time reading the English translation, but the language of the Chinese translation I originally read and the language of the English translation are both fairly unremarkable, so I didn't have as varied of an experience as I did with, say,
Angel Sanctuary.
Aso Kira is quiet, terminally shy, and devoted to her art, but she's also bullied by the girls at school. Kashino Rei is just the opposite in personality, although equally as devoted to motorcycles and motorcycle racing. They meet-cute in a park, and while Kira is terrified of talking to him because of his bad-boy reputation, she uncharacteristically overcomes her shyness and ends up asking him to model for her.
This series is an odd combination of quiet character moments and Gothic romance/horror, which Soryo mixes together more successfully with her later series
Eternal Sabbath (ES). Even so, I ate this up with a spoon the first time I read it. There's revelation upon revelation about Rei's past, along with a few psychopaths, mental trauma, and parental disapproval. My favorite things about the series is how Rei and Kira actually talk to each other, how Soryo doesn't forget about Rei's friendship with Tatsuya and Kira's eventual friendship with a girl in her class. I also like the explorations of hate and anger, particularly with Kira.
My biggest beef with the series (aside from now rolling my eyes at some of the subplots, particularly the early one about Rei's old girlfriend) is similar to my problem with many shoujo series. Rei's story eventually eclipses Kira's; he not only gets more angst and action and stuff to do, much of the focus ends up being on what he feels and why, with Kira there to provide support only. We don't even get much of Kira's POV on being the support, particularly near the end. Kira does get some angst later on, but it's pretty telling that the last shot of the series is of Rei alone, looking up to an empty sky. (I think? I returned it to the library so I can't double check.)
Still, I like that Soryo is committed to portraying the two in a working, evolving relationship, as opposed to drawn-out misunderstandings and other reasons to keep the couple apart. I especially like watching Kira grow throughout the series; Rei does give her strength, but a lot of what she accomplishes is on her own terms, even though it's often sidelined.
Please put any spoilers in the comments in <span style="color:#333,background:#333">spoiler text</span>!