The two biggest advantages to outsourcing BIM are cost and time.
Cost
In most cases, a single BIM project can cost thousands of dollars in programs and overhead to perform your projects BIM deliverables. By outsourcing your BIM, you will receive quality fabrication ready drawings and models at a fixed price set before the project begins. By outsourcing, you can count on the markup from the fixed price set by the BIM provider and not concerning yourself with possible cost overruns by performing BIM in-house. This is especially true if your company only does a few BIM projects a year. Let your BIM service provider absorb all the additional operational costs of programs, overhead and maintenance involved with BIM allowing you to allocate your money into other aspects of your business.
Time
The most valuable advantage to outsourcing is time. Save valuable time by outsourcing your BIM to an experienced provider. In many cases, BIM is becoming a project requirement and is sometimes required just to qualify for a project. By outsourcing BIM, the entire construction process is simplified and successful. Let your BIM provider use the models to benefit you company. BIM can be used to find discrepancies, prevent errors, avoid setbacks and produce quantity takeoffs. Your company is the best because you specialize in a certain field. Consider outsourcing BIM to a company that specializes in that very field.