I had 3 flights with eznis - from Buyant Uhaa (ULN) to Murun (MXV), from Murun to Dalanzadgad (DLZ) and back to Buyant Uhaa. As a result I had 2 flights delays for 6 hours each (so, the whole day was lost which of course affected my travel plans). Very poor English of the staff even in head-office and nobody knows what is going on. The third trip from Dalanzadgad to Buyant Uhaa wondered even myself. They moved me and my wife from the 9 am flight to the 5 pm flight (most likely to fit into the plane an organised group of tourists) and I found it only when I was trying to check in. I would recommend this airlines only if you are happy to lose 3 full days of your trip and stuck in the middle of nowhere for a day or so. Onboard service however is good enough.
"Group" tickets: The price of the tickets for lowcost flights increases with the number of tickets sold. So it may happen that there is only one ticket left at the lowest price (e.g. 30Euro) and that the others cost more (e.g. 40Euro). If you buy two tickets, you will be paying the higher price multiplied by the number of passengers (in our case 40*2=80Euro, instead of 30+40=70Euro). Always check that the total price for the group is not higher than the initial price per person multiplied by the number of people in your group.