In short
Ethiopia was never colonised, apart from five years of Italian occupation. It kept its script, Ge'ez, its thirteen-month calendar and a clock offset by six hours.
Addis Ababa is the seat of the African Union and a major air hub for the whole continent.
What it really costs
The city is cheap but currency is a subject: the birr is depreciating, and official and parallel rates diverge. Finding out before you leave matters more than the choice of accommodation.
Coffee was born here. Coffee ceremonies, long and codified, are a daily practice and cost a few birr.
What nobody tells you
The altitude is two thousand four hundred metres and tells on arrival. It also explains the temperate climate of a city close to the equator.
The Ethiopian calendar runs seven to eight years behind ours and the local clock counts hours from sunrise. Confirming appointments in "European" time avoids daily misunderstandings.
The security situation varies sharply by region and there have been recent conflicts. Addis Ababa is not affected in the same way, but any itinerary outside the capital should be checked against official travel advice.