Quality of the stock - looks better, has better finish, and is typically more accurate because it's a better fit to the receiver and doesn't flex to touch the barrel/is free floated
Detachable Box magazine (some models), so you can pull your bullets out through the bottom instead of chambering and unchambering each round.
Quality of finish on the rifle itself - looks better or is more weather resistant.
And there is possibly some other changes, but the 700 ADL is (to the best of my knowledge) something they sell only to specific stores, so I don't know everything about it. I own a 700 ADL from back when it was their standard rifle, and think its great, but don't know about these.