The hotel is located on the Danube river. Very beautifull building. Friendly staff, nice lobby where they have live music playing every night.
Our room vas clean, but small and a little old looking (actually, the hotel looks like it needs some renovation). Still, the room had a little balcony and a nice river view.
The location is also good: There is a tram stop two steps from the hotel and it only takes 5-10 min to get to downtown. In fact, Gellert is the most famous hotel in Hungary. It's mostly famous for its spa.
The spa has several pools with warm mineral water and a regular pool. It also has men/women sections which have mineral pools. You can also get a very cheap professional massage - but it does not look so good. There is no privacy: I saw a woman getting a massage, lying naked in front of everybody in the dressing room.
Don't go on a weekend - it is crowded with locals.
The spa is very big and stunning but it also needs a major renovation. It is state owned, so don't expect friendly treatment.