Palais Coburg (LHW) you find directly behind the Marriott, which is located at Parkring opposite Stadtpark / City Park (where you can find restaurant Steirereck and Kursalon). The location is good as you can reach in 7-8 mins by walking via Weihburggasse (at the side of both hotels - I stayed at the Marriott) Kärntner Strasse pedestrian area near Stephansdom.
Sacher Cafe is targeted by tourists, same as partly Sacher Eck. Restaurant Rote Bar which I visit often (main entrance and then right, view to Opera) and Restaurant Anna Sacher (in the rear of the hotel after Blaue Bar) are serving excellent Viennese cuisine to hotel and opera guests and locals. For me and most of my German compatriots Sacher is THE luxury hotel in Vienna, beside Imperial of course. The rooms are nicely renovated and up to date.
I would admit that Park Hyatt is probably the best international luxury hotel in Vienna if one doesn´t care about icons, history and old Viennese atmosphere. Dining at the restaurant "The Bank" is a must. Excellent food, service and incredible atmosphere in the renovated awesome former bank hall.