With a clean, easy to use user interface, the best documentation of the bunch and excellent customer & technical support, we feel you cannot go wrong with iEmulator. Although USB connectivity is not as complete as a hardware-based PC (a common complaint with PC emulators), iEmulator.com has been releasing updates every couple of months (at no charge) which are addressing any shortcomings the product has. Our one complaint is that installing Windows is too much like a hardware-based PC: there's no "wizard" to guide you through the process, although the documentation does address this with excellent step-by-step directions. With the lowest price in the emulator market and competitive performance, iEmulator a winner.
Link: www.iemulator.com

Virtual PC 7.0.2

At times, it seems that Microsoft's Virtual PC has been around as long as the Mac has, and it shows: Virtual PC is the most mature emulation application for the Mac, offering the best integration with OS X and the highest performance PC emulation available. All of this comes at a price, though: major upgrades have not been free of charge, and the price of entry is high: double Guest PC's and over five times iEmulator's cost. In addition, technical support can be an issue: our request for assistance went unanswered. Virtual PC is a great application but it's expensive and we question Microsoft's commitment to the product.
Link: www.microsoft.com

Guest PC 1.6

Guest PC disappointed us. We expected a product close to Virtual PC but at half the price, but it didn't deliver. Performance was good: comparable to iEmulator, but stability was an issue, both within the Windows environment as well as with the OS X application. We were only able to finish a single benchmark in Windows 98, and could not get WinTune to run a complete test in Windows 2000 or XP without crashing. In addition we noticed some inconsistent math emulation results, with simple calculations giving incorrect answers in Excel and a popular tax preparation application. Lismore Systems has been releasing no-charge updates at a good pace, and we're hopeful that they will be able to solve these issues soon, but for now we cannot recommend Guest PC.
Link: www.lismoresystems.com