We were in town for only two days and nights, and needed a nice hotel that was proximate to everything we wanted to see. The Ring was a fantastic choice in every respect - I can't recommend it highly enough.
The hotel itself is a recent renovation of an older building, with all of the modern amenities (beautiful and clean rooms, flat screen TV's, etc) one could want from a modern luxury hotel coupled with the beautiful features of an older building (cast iron elevator, pretty terrazzo tiled floors). Our room on the first floor and faced the Kantner Ring (the main street) but was perfectly quiet throughout our stay (the Vienna trams are whisper quiet). The room was quite large, clean, well air-conditioned, and tastefully appointed. The hotel staff was wonderful - accommodating, polite, charming and quite helpful on each occasion we reached out to them. We didn't try the restaurant, but it appeared popular with locals and had a nice "fusion" Continental feel to the menu.
The location is to die for - a block from the Staatsoper (Vienna State opera), a 5-10 minute walk from most major attractions (the Hofsburg palaces, Museum Quarter, Parliament, Belvidere Palace, Stadtpark / Steirereck, Wien Museum, Wiener Philarmonic, St. Stephensdom, Hotel Sacher, shopping, the DO&CO, restaurants etc.), and right on the subway (Karlsplatz) for easy access to all of the other sites one would want to see.
Very Highly Recommended.