From what I have heard and read, I think Ethiopian is one of the better airlines. Addis Abbeba is also a very nice place to live, in my opinion.
EVERY airline has it's naysayers. Is Ethiopian the best? No. If I were you, I would investigate a job there, and not just blindly turn it down.
I have heard that Qatar, and living in Doha is not very nice. But, I know a pilot there, and he and his wife like the airline and they like living in Doha. The same goes for Emirates and Dubai.