After a long flight from the states, and the train to the Hauptbahnhof, I needed to get rid of my suitcase for the rest of the day. The Plaza Hotel was close to the train station. The staff allowed me to leave my suitcase in the little office as it was only about 9 AM. They also were kind enough to make me a cup of coffee to go at the little lobby bar.
Extra charge for breakfast.
Tiny elevator.
A short walk from the river - perfect for morning walks or evening strolls. On a quiet street, close to a little park. Clean room. My single room was about the size of a single ship cabin. Tiny, but adequate for my one night stay. Only complaint was the shower. Needs a step-over so water doesn't come out onto the floor. Needs shower doors to replace the curtain (which I didn't use because it just blows back into the shower.) Fortunately the entire bathroom is tiled. I prepaid $70 for this room.

I've booked two nights for double non-smooking room. As I've arrived late in the night, and they did not have non-smoking room, they put me into a single room, that was the only non-smoking left. The first night I had to spend in the smalles single room I've ever been..
It is actually an upgraded hostel-style hotel, very clean but very basic. Bedlinen old, 1000times washed, with holes, TV-remote-control old, does not work properly.
Next night I spent in the double room, was much better, although do not expect any nice double-bed, it is actually two beds put together. Bedlinen the same old stuff.
Checking out: they tried to charge me the breakfast, so I pointed out that I've paid for double room, and I had to spend the first night in a single, so I thought breakfast would be complementary. At the end, they did not charge the breakfast, but would have been nice if they offer it.....

Stayed for one night in this hotel in a single room. Room size was quiet small but was very clean and had a verandah and a roomy bathroom. Was 10 minute walk from main train station .Staff were very helpful.Internet cafe just round the corner as well.

This hotel exactly suited our needs. We planned to base in Frankfurt and take the train daily to other destinations in Germany. The Best Western is about four blocks from the hauptbahnhof (second largest in the world, I'm told) and an easy ten minute walk. We frequently took the walk home at night and saw nothing alarming. The rooms were Europe-small but quite comfortable and ours, located at the back, relatively quiet.. The hotel was clean with polite English speaking personnel. The rate for a double room for six nights was 640 Euros, which I considered quite reasonable. It was a quite enjoyable experience and I recommend the hotel to anyone with goals similar to ours traveling to Frankfurt.

I gave it an above average rather than an excellent for the sole reason that the on site breakfast was 12 Euros per person, somewhat high for small-breakfast Americans.