Not a bad resorce for a generalist rather than ballroom-specific website.
Some issues though:
It would be good to have some explanation of the range of tempos and what they are suitable for.
Also some comments on strict tempos verses more artistic interpretations, especially for some classic standards
No citations of specific recordings - this ties into the above. Also the very real problem of where to find the stuff. Realistically, it's going to be hard to save money buying dance music from anyone but one of the specialty publishers who collect, group, and if necessary re-record tracks. This is especially ironic when you seem the names of specialty outfits (Tauber, etc) listed without explanation of their role.
Although there is a seperate Viennese section, the Waltz section contains some Viennese Waltzes that are not identified as such