I have flown only with Qatar and loved it but to my knowledge, Etihad is also a good airline (and you are provided free accomodation).  It may,therefore, not be worth paying the extra bucks in Qatar.  I would stay away from Emirates.  While Emirates itself is a well-rated airline, your connection from Dubai is probably on Fly Dubai which is an LCC with not the best reputation.  All that said, if I were you I would take Etihad.