The apartment itself is really lovely. It's a historic building with high ceilings and architectural details that combine with tasteful furnishings to feel homey yet glamorous. The heat / AC works great, the kitchen is large, and there's plenty of room. Location is good as well, on a quiet street close to nice Thissio restaurants and the lively Monastriaki and Psyrri areas.
However, there were also a few things I didn't like quite as much - The internet was really slow - it was just about ok for recreational use, but wouldn't play Netflix in full resolution and I wouldn't have been able to use it if I had to work. This was also the first AirBnB I've stayed at that's tried to charge (and charge a high price - 10 euro for each every day) for a high-chair and crib for an infant, so I didn't like that. Also had some issues with the hot water going out while we were showering which is probably something that's easily fixed but affected our stay.
So overall a beautiful place in a good location with very responsive hosts, but a few issues for us which may or may not be an issue for you.