Darcy's Story is about the best I've come across. It reads more like a contemporary of the novel. Darcy's Diary is...adequate but not great. Would not suggest purchasing it before reading, as I did.

I might look for Darcy's Story at the library when I'm home.

Some are good, some are bad. I suggest trying ones at a library before buying. Some I'll gamble on but I've read a lot and can kinda see the warning signs for me. I'll give most any of them a shot, except for modern retellings...except for these new ones from the Austen project or whatever it's called.