Over and above the obvious factors which have already been discussed here such as pay, l think everyone is chasing lifestyle and that is what you must consider when choosing jobs. Do you want to be home every night with your family in the house that you are paying a large slice of your earnings to own or are you happy to be away staying in nice 5* hotels?
Sounds obvious and dont get me wrong they are both good on their merits but only you can decide what you want out of your flying career vs home life.
As for burn out and working practices, there is no "golden job" any more and l think everyone works pretty hard now so again you need to think what is good for you. EZY offer the fixed roster but BA offer trips away in exotic destinations...what would be best for you?