This is a wonderful airport, BUT flight registration staff is totally incompetent. They often refuse to register on flight without any legal reason. It happens with Armenian citizens and foreigners, because airport staff doesn’t know visa rules for different countries. Shame on them, it ruins plans and wastes tons of money. This doesn’t fit an “international” airport at all.
Bathrooms remain abysmally filthy and this has been a problem for many years. Airport is obviously unwilling to do anything about it. I don't think the cleaning staff has the training or the supplies to do a proper job. At this point, probably the only solution would be to rip out the old stinky bathrooms and replace them. It's that bad.
One of the worst airport I've ever been. No drinking water. You have to buy it. Registration opens only 2 (or maby 3, you cannot know in advance) hours before departure. So AVOID for the sake of your life long transfers here. There is no charging stations in arrivals or departures area, where you will wait for the registration. But don't worry there's no comfortable seats too, so you couldn't use your laptop or even charge something. Cafés are more expensive than in the biggest European airports.
Transfer from/to this airport will be a real quest for you. There is no normal busses, just mini-buses (called "route taxi"), which you could pay only in local cash and which departures only twice an hour. The quality of driving is the worst that you could imagine.