Muses are one of the most useful and most taken for granted technologies of the post-singularity world. The constant labors of the personal assistant AIs have eliminated secretaries, receptionists, supervisors, and many managers, as well as general practitioners, many therapists, and earlier AIs. The efficiency gained through their pervasive use cannot be fully calculated, but many are confident it can still be increased.
The difference between a daemon and a muse is simple. Instead of working through the inefficiencies of spoken language, or displays, a daemon has a direct line into the brain. A daemon's advice is not spoken and not heard, instead it is immediately comprehended. The benefits of this close union are an increase in effectiveness across the board, because, although the muse's AI is not upgraded, its ability to interact with its user is greatly increased.
Although muses have gained acceptance from bioconservatives and those afraid of AI through sheer practicality, daemons are another story. Large segments of most populations do not want to give an AI a direct brain interface.
A daemon is a muse with a cyberware upgrade [Moderate] giving it direct access to the brain.
A daemon gains +5 to all skills. There may be other benefits at the GM's discretion.