The fight against "default" white seems analogous to Ian Storm Taylor's recommendation to never use black (http://ianstormtaylor.com/design-tip-never-use-black/). I prefer off white (e.g., #f9fafc) because of the same reason I like text color set at #333 — it looks softer, but still almost imperceptibly different from #fff/#000's traditional "paper and ink" aesthetic.