I remember when subs2srs came out and CB posted his sample deck for 時をかける少女. Well, before I had a good baseline for grammar or vocabulary I tried to learn from that. Very quickly gave up and stuck to finishing vocabulary and basic grammar lists. The merits of learning from entertaining native material is there. The problem occurs when you attack it too fast before there's a solid foundation to approach from.
Personal opinion, but I like to study dramas with subs2srs as you get all those side benefits: varied voices, listening material, reading material (from dramanote scripts), cultural material. Doing the same with a book takes the same amount of effort, but limited secondary materials. On the other hand, a book has much more dense material and the descriptive narrative differs from spoken dialogue.
Personal opinion, but I like to study dramas with subs2srs as you get all those side benefits: varied voices, listening material, reading material (from dramanote scripts), cultural material. Doing the same with a book takes the same amount of effort, but limited secondary materials. On the other hand, a book has much more dense material and the descriptive narrative differs from spoken dialogue.