Board Thread:Questions and Answers/@comment-209.48.134.190-20150703220239/@comment-6697950-20150706225605

The manga are mostly all adaptations (aside from Girls Ops, which is a spin-off), and some of them are worse than the anime adaptation. And if you haven't noticed, there have been quite a few anime that were based on novels rather than manga. E.g. Log Horizon, No Game No Life, Mahouka Koukou no Rettousei, Date A Live and so on and so on. So, unless you're living in the last decade, Sword Art Online isn't really unique in that aspect.