Since she lived a hundred years later than Austen, Heyer had the disadvantage of having to research the manners and mores of the time. However, according to rumor, her grandmother who lived with her family was raised during the late Regency and became Heyer's model for her Regency speech and customs.
Some critics find Heyer's novels filled with too much detail, others consider her detail to be her greatest asset, with her wit coming in as a close second. She wrote not only Regencies, but other historical novels including one about William the Conqueror hailed as one of the most historically accurate writings about the long ago King of England. She also wrote contemporary novels and thrillers.
I admit I haven't read all of her books, but I plan to. Of those I have read, here are my favorites: