skywards,you are right, but as you know things can change immediately!!!
maybe today you chose one airline that pays you more, and after 1 year, te salary changes and you can earn a lot less...
Maybe in one airline, with your professionality you can become a Cabin Crew Manager after 4 years, and in the other after 10 years, or eventually, you can't improve your future career.
Just go where you feel it could be better. As we all see, one week you have a job, the week after you don't even have one. So, don't chose just about 100 or 200 dirham more or less...