The Living Force
I've read the 3 first books of the Survivors series of Mrs Balogh (The proposal, The arrangement, Only enchanting). I liked the Mackenzie series and will come back to it, but to me the Survivors series is superior in quality.
I would agree and also add that different authors brings different things to the table. Taking the above mentioned series, Ashley is better when it comes to communicating about passions, despair and other strong emotions in her characters, she makes those things more vivid, while in Balogh's writing it's more subdued and intellectualized. But then, Balogh is so much better when it comes to psychological and philosophical insights. Among other things, I also appreciate the fact that the Survivors' series doesn't follow the usual denouement of someone getting nearly killed by the end of the novel, which seems to be characteristic of most of the recommended series.