I don't like the ceramic mixed with stainless. If it were my first "good" watch, I'd pick a different Cartier, but if you already have a collection, and are looking for a ceramic, I'd go Chanel.
Chanel for sure. I have the white with diamond markers and it's very easy to dress up or down. For Cartier I prefer simple stainless steel watches, like the tank francaise or ballon bleu.
If it's between the Cartier Chronograph or Chanel J12, I would pick the J12. Usually for watches though I would pick Cartier. I love Chanel handbags, but think Cartier makes better watches.