The Lochner is in Markelsheim (not Bad Mergenteim, as appears on some sites). Markelsheim is a charming wine village situated under impressively steep vine slopes.
The hotel is as charming as the village. It's a classic old German building into which they've somehow managed to install lifts. Some of the floors are on "half-storeys" so not all the rooms avoid stairs.
There was ample parking at the back, though the spaces were tight. After a very hot day, my room was a bit warm at night, even with the window ajar, but not uncomfortable. I had a single room, which was large enough.
As the hotel filled up, the wi-fi in my room slowed and would often drop out. Tolerable though.
There's a lovely big indoor at about 28C - perfect on a hot day - and a sauna, which no-one used that day.
The breakfast was a normal fine German breakfast.
The staff were very welcoming, though with some I found it better to communicate in German than in English.
I enjoyed my single night stay, but I probably wouldn't want a long stay here.