I was safety pilot for a New DEP on day one a few weeks ago from Emirates. I've met other FO's down route/on crew bus etc that have come from Qatar & Etihad in the 2011 Recruitment campaign. All have their own personal reasons for coming home, most said they enjoyed it while it lasted but didn't want to have a 40 year career in the ME. Good job but not a long term career for them.
However I have friends from my OAT vintage (calling Oxford OAT is vintage these days) that are out with Emirates/Etihad & love it. So it's purely down to personal choice of what works for you & your family etc. Equally I've heard several crewmers that a few guys have left BA for Etihad/Emirates etc. No airline is perfect! I imagine tho the bulk of DEPs are still coming from Easy/Monarch & alike. BA is not the be all & end all but as a long term stable career it works for me, especially if you want to be in the UK or Europe!
All the best to those applying.