All true, although I would quibble with: > That's such a simple operation that it will typically be as fast or even faster than a single pop-one-message operat

All true, although I would quibble with: > That's such a simple operation that it will typically be as fast or even faster than a single pop-one-message operation in an MPSC/MPMP. Not if the lock is blocked because one of the writers context switched out! The typical case is good, but the worst case is pretty bad.