Win4BSD is a PC emulator that runs Windows as a guest at nearly native speed under FreeBSD/PC-BSD. It is based on QEMU. However, Win4BSD offers many advantages, including improved speed, ease of use, more seamless integration with the host OS, and “grabless” mouse transition between the host and Windows
Win4BSD was built by Virtual Bridges to detirmine the level of acceptance by the FreeBSD and PC-BSD community for high-grade commercial software. After two years, we have concluded desktop BSD-oriented applications are best accepted by the non-commercial community when offered at no charge and made freely available.
Source: Virtual Bridges Blog