I made the mistake of taking a First Officer position with Oasis Hong Kong Airlines based on a promise of a quick command as I was already a -400 Captain with Dragonair. We all know what happened to Oasis. It took me less than 2 months to work out that I would stagnate and go backwards in my career if I didn't get back into the left seat quickly. Thank goodness they went bankrupt as quickly as they did. I got lucky and was back into the left seat of the A330 after 8 months of being employed. Lesson: never go backwards in your aviation career, always move forward and up. With your background of the A320 it would be a catastrophic career move to accept a Second Officer position with CX.