Bösendorfer pianos are widely considered to be the only other piano in anywhere near the same class as the legendary pianos manufactured by Steinway & Sons.
"On 25 July 1828, Ignaz Bösendorfer was issued the trade license number 225 669, and with it the right to take up residence in Vienna, to manufacture pianos, and to pay taxes. This sober award marks the beginning of a great and glorious history of a piano house that has not only been closely linked with Vienna's musical development throughout the 19th, 20th and 21st centuries, but has also been the sole piano maker to continuously uphold the Viennese piano making tradition, continuously developing and refining it to the present day."
Source: www.bosendorfer.com