Best avoided.
From the point of view of being next to Frankfurt Station, it is very convenient, but the area is disgusting; full of drug addicts, pickpockets, drug dealers, drunks, the homeless and prostitutes.
The breakfast was included, which was pretty good and the staff on reception are extremely nice and patient, especially given the number of people complaining. I had to change rooms as the furniture (which looked like it had come from a skip) was broken and there were problems with the plumbing. In each room, the beds were clean and comfortable, but the paint on the walls was peeling, there were severe problems with the plumbing (toilet in one, shower and sink in the other), there was mould and water damage on the walls and ceiling, stains on the curtains and carpets, and the property generally looks like it is being run into the ground by owners who couldn't care less. Also, if you're a light sleeper, avoid this hotel as the noise from the street (trams, sirens, people fighting, drunks shouting at each other) even with earplugs in, is unbearable.