Personally I believe that no filter communication works best in conveying ideas clearly and directly. However, it only work if there's established trust and respect in the relationship. In addition, no filter doesn't mean be abrasive (like Linus). I've found that with some pretty competent people they can shutdown in those situations. Clear, honest, no fluff communication is essential, but it's also essential to keep the conversation about the work and not about the person.

A combination of appropriate encouragement, honest criticism, and healthy respect is needed to bring out the best in people.