The one you are most comfortable with and feel you will end up working the most to.
When you consider that they have expanded API 1104 the past couple of editions and that D1.1 MOSTLY tests from Clause 2 -6 (only about 1/2 the book) there is really not that much difference.
If I had to do it over, I would stick with D1.1 which was my original.
Both have their own quirks, positive and negative.
He Is In Control, Have a Great Day, Brent