After having arrived at 5.30pm (while check-in started at 3pm) we were told our room was not yet ready without any indication of how long it would still take. We were advised by a very unfriendly receptionist to go away and come back a few hours later to see whether our room might possibly be ready by then. Not to create a fuss, we decided to leave our bags behind and go out for dinner, only to come back at 9.30pm and find the receptionist to be just as unfriendly as before, if not more. After another wait, he showed us to our room, which was located at the end of a hall with lights that didn't work properly, and had two single beds, even though we had requested one large bed.
Asking the receptionist to do something about this, he told us he would have to check whether he could do anything, and that this would take some time, hinting that it would just be better for us to take the room we already had. We insisted he would check on another room, so he did, and unfortunately this took another 20 minutes.
The rooms themselves were surprisingly lovely, but the attitude of the receptionist completely ruined our stay. Also, his colleague the next morning was not much friendlier, so in the future, should we ever return to Garmisch, we will do anything possible to avoid Atlas Sport and its unfriendly staff.