А чего они советуют? :)

Нашла место в Дебретте:

"...That being said, 'Mr' lacks both style and distinction, and I would still recommend using Esq. in all social circumstances and most business ones. The ugly-sounding Ms is also problematic. Although many women have assumed this bland epithet, it remains incorrect to use it when addressing a social letter. Its role, if used at all, is confined to the business arena."

Morgan, John. Debrett's New Guide to Etiquette & Modern Manners. p. 174.

Ну, я деловых писем практически не пишу, у меня вся переписка светского свойства :-)