But even Boot Camp is only second-best. The best option for Mac users who are also heavy Windows users is two computers: Get a Mac and a PC and network them together.
Windows-on-Mac newbies: What if you're a first-timer, and you've never run Windows on a Mac before? Should you buy Parallels, or Fusion? Of the two, I think Parallels 4 is a little better. But just a little. And I expect that Fusion will one-up Parallels when Fusion comes up with its next version.
Parallels beats VMware on performance. I think it's a better-looking product, too -- although that's an extremely subjective measure. It supports more advanced graphics. And the additional bundled products for Internet security, disk management, and backup make it a better value -- if you need those products. If you don't need them, then they're irrelevant.
But I can't give my wholehearted recommendation to Parallels. The product's history is tainted. Parallels 3 was a lemon, and a company that comes out with a lemon once might do it again. You might be happy with Parallels 4, but find that Parallels 5 is a dud, and you've spent money on a dead-end product.
Moreover, while I didn't find any significant bugs in Parallel 4, other people have. Or they claim to. Users are complaining on the Internet about problems installing Parallels 4 and getting support. For example, see these Lifehacker comments from rychdom, and Durbrow (with replies). NineTailedFox writes: "The application is named 'Parallels' on the basis that there may be parallel realities in which I'm happy about being charged $40 to upgrade a piece of software which has never approached acceptable performance."
Normally, I'd write those off as a vocal minority -- any new product, no matter how good, will create problems for some users. But given Parallels' troubled history, I'm reluctant to simply dismiss the complainers' concerns.
Fusion 2 and Parallels aren't the only two options for running Windows apps on Macs. VirtualBox is open source virtualization software that runs on the Mac, Windows, and Linux.
Another alternative, Crossover Mac, from CodeWeavers, is an implementation of the Wine open source Windows API. Because Crossover isn't actually Windows, it doesn't support all Windows apps, but it supports many of them; the company maintains a database of compatible apps, including the Microsoft Office suite, Lotus Notes, Quicken, and popular games like Half-Life. CodeWeavers also has a version that runs on Linux. It's much less expensive than Parallels or VMware, priced at $39.95 -- and, unlike Parallels, VMware Fusion, and VirtualBox, you don't need a copy of Windows to run Windows applications on Crossover.
Overall, Parallels 4 is a huge improvement over the previous version, and a small but significant improvement over the leading competitor, VMware Fusion 2. It's your current best choice for virtualizing Windows and Linux on the Mac -- if you're willing to overlook its shady past.