It’s been about 5 years.. but I used to fly Dulles to Addis 4-5 times a year over the course of a 3 year period, with between a 4-6 layover in Addis each direction depending on my next connection..
The 787 that flies between IAD and Addis is a nice, comfortable bird… in flight entertainment is decent.. food is reasonable, etc.. and the flight attendants were always friendly and helpful…
But Ethiopia Air is certainly a step or two down from flying with a true premium carrier like Qatar, Emeriates, Cathay Pacific, etc..
The airport in Addis leaves quite a bit to be desired… there’s some ok curio shopping with well priced items.. but most of the shops close early and open late.. depending on your arrival and departure times, you might find little to do there on a layover..
The lounge isn’t particularly great..it’s clean and reasonably comfortable.. but don’t expect anything close to luxury..
Restaurant options are extremely limited.. on the back side of the terminal, opposite of the gates, on the far left there is a decent place to eat that serves traditional Ethiopian food, ice cold St. George beer, and piping hot traditional Ethiopian coffee.. other than that your options are pretty limited.. there’s a sandwich shop type place with a few hot options and a couple of places have snacks and sodas, but that’s it..
During peak times the airport is ridiculously crowded and there isn’t nearly enough seating.. so if you want a place to sit and see something available, grab it quickly.. and don’t get up again, or it will be gone…
Overall I enjoyed flying Ethiopia Air and doing the Addis route.. my other options were to fly into Nairobi on Kenyan Air or on United.. or to fly into Abu Dhabi on either Emeriates or United and then connect to my end destination (generally either Juba, South Sudan or Entebbe, Uganda).. and I almost alway chose Ethiopian (knowing that Emeriates was nicer)..due to the flight times and layovers being better, price usually better, and Ethiopian never actually disappointing me in any way..
Just don’t expect a super premium experience and you’ll be great… it’s certainly better than flying Aero Mexico, Taca, or some of the Western Hemisphere airlines I’ve had to over the last several years…