Boost is always my last resort.

While Boost often implements the latest proposed standards and provides a vast extension to the STL, it is not the STL. Often proposed standards changes are best implemented by changing the compiler itself. Expecting Boost to provide the same functionality as a modified compiler without a cost is foolish.

Boost provides great implementations but at a great cost in complexity, compile time and binary size bloat. I don't even really believe modules will solve this. They push the boundaries of what is possible with today's equipment, in order to discover what the next equipment should be.

Also I no longer look to Boost libraries as a Seal of Quality. There be dragons. Choose wisely.