Multisim is described as 'Is industry-standard SPICE simulation and circuit design software for analog, digital, and power electronics in education and research' and is a circuit simulator in the education & reference category. There are more than 25 alternatives to Multisim for a variety of platforms, including Windows, Linux, Mac, Web-based and iPhone apps. The best Multisim alternative is Circuit JS, which is both free and Open Source. Other great apps like Multisim are QUCS, LTspice, Altium Designer and Proteus PCB design.
Its a good basic tool, but once doing anything past the pure basics its falls short really fast.