This hotel is a major mixed bag.

The positives: Room was spacious, comfortable bedding, very nice spa/indoor pool/steam room/sauna, amazing views of the Acropolis from the rooftop pool and bar (having a drink there at night was the highlight of my stay)

The negatives: The location is very sketchy. It is surrounded by three huge strip clubs with prolific signage. I would not recommend it for children. It’s not in the heart of the city, so you need a 5-10 minute taxi or shuttle to get to the main attractions. The food offerings in the concierge lounge were terrible, and there was trash all over the floor. I propped up my feet on a coffee table because of the trash (mostly nuts). I was promptly asked my a member of the staff to remove my feet from the coffee table.

By far the worst problem is the check-in. It was HORRIBLE. I would estimate I waited 30 minutes in line to find out my room was not ready and that I would have to go back through the same line later. I heard many other guests complaining about it and have seen this comment in many other reviews. The front desk was chaotic every time I entered and exited the hotel. I feel sorry for the staff, because they were very nice. This is a management issue. There is absolutely no excuse for management to allow the hotel to be woefully understaffed and for its processes to be so inefficient. Start by cross-training staff to assist with check-in! Plan to spend a long time in line. Or stay somewhere else.

Nothing Grand about this Grand Hyatt. In a country with abundance of warmth and solid hospitality, this was a strange outlier at the end of our trip.
Poor Service across the board
Super unwelcoming staff
Average breakfast in terms of spread and quality
Tiny bathrooms
Overall seemed understaffed
Very to the point - 3.5 starish attitude overall.
Disappointing to say the least.
@Grand Hyatt as a brand this affects you more than the hotel which seems to be doing well. I’ll think many times before booking another Grand Hyatt knowing usually it’s a fairly solid product. But maybe there is no brand oversight.

We picked this hotel because of the adult infinity pool and the view of the Acropolis which did not disappoint however there were kids at the pool and this was not enforced.

The Front Desk staff was fabulous as they were a professional and friendly. but everyone else was not Our refrigerator didnt work and we had to order ice twice a day.

I felt like I was in downtown Baltimore city as there were strip clubs and sex shops nearby but that did not bother me. If I stayed in Athens again, I would stay at a smaller boutique hotel closer to the Acropolis.