Don't normally write these but felt compelled after reading some of the other comments. All I can say is, if there was a problem before, they've got it sorted now. Went with some friends on Saturday and had a brilliant night! We were early so had a cocktail first (Berry Caipiroska, lovely) after which we were escorted to our table in the packed restaurant.
Despite the number of people eating (or maybe because of it?) the staff seemed to be enjoying themselves, which I think is always brilliant for the atmosphere and our waitress was friendly and efficient, without making us feel rushed. I started off with the mussels and then had the steak which was just perfect with a beautiful béarnaise sauce. The waitress recommended the pavlova, which was strawberry that day and which all but one of us ordered and it was gorgeous, I will go back just for that! I wouldn't call it cheap, but it was certainly good value for money, as a fab night was had by all. Kettner's is one of those places I'd been aware of for years but never had actually gone into and it's instantly become one of my favourite places in Soho and I'd go back anytime!