I can honestly say I had not heard about AutoFixture until today. Haha.

They look similar. The only difference I can really see is that I prefer my syntax a little better for type fixtures:

.For<string>("whatever"); vs fixture.TypeMappings[typeof(string)] = s => "whatever";

I also allow a seed to be set for ensure "consistent random data".

But there are some features of AutoFixture that I definitely want to look at.

I created Fibber more for mocking data sources when I was creating Web Api services; and AutoPoco was just too much configuration. Unit testing was not the main purpose of the library.