Visited the Rosenstein on our last night following the hotel recommending plus reviews on TA.
Only a 5 minutes walk and yes the area is not brilliant and it does appear a little quiet and secluded but once through the doors it's a different world in a good way.
We made a reservation beforehand and also would recommend that you do the same as the tables quickly fill up. There was a mix of tourists plus locals which is always a good indication of the quality of the food.
The menu is extensive and heavily meat based but am positive they would cater for all tastes. The staff certainly knew the menu well and were able to answer all our queries. The food was simply amazing popping with fantastic flavours and the portion sizes were very ample. Overall my boyfriend and I had a brilliant last evening in Budapest, left full and very happy with our choice of restaurant.
I can't praise the restaurant enough apart from go and see for yourself!!!