Switching to NoSQL for native JSON use?
Are the performance gains from data consistency enough of a reason to develop in NoSQL, rather than relational?


I think your question presupposes a certain way of looking at things.  Your fundamental tradeoff with NoSQL is a tradeoff between declarative ad hoc reporting and fast and loose inputs.  This tradeoff is unacceptable for many (maybe most) businesses, and so "rather than relational" I think is the wrong way to look at it.  Even folks like Martin Fowler advocate something different.

My recommendation is always to start relational and then add NoSQL adjuncts to the rdbms to handle velocity issues when those arise.