The "sexist" (if it even applies as sexist) logo doesn't even bother me. I think it's hilarious, and says that the company has a sense of humour and they're not afraid to show it. She is clearly a "larger" than life representation. I think she looks great, even if she has some side boob showing. It's boobs, so what.
If someone gets upset by a hyperealistic cartoon girl, that's their problem. They hired Serge to do this logo for them, they knew his style. If that's what the client wanted, that's what he got. I can see how some people would get upset, but it's just art in the end.
I admire your use of detail and design, as well as your rendering and composition, but I think the hypersexuality of the female is unnecessary and dominates the image. While the latter may have been intentional, I think it's too much.