Oh, goodness me, very much so.
VirtualPC was absolutely terrible at what it did, even for a virtualization suite.
Because the OS is being virtualized, it cannot access the full potential of the hardware and would thus run very slowly. Boot Camp, on the other hand, runs Windows natively, giving it the same access to the hardware as OS X.
Current virtualization software, such as Parallels and VMware, do their jobs MUCH better than Virtual PC ever did, because they don't have to emulate an x86/x64 processor, among other reasons. In fact, for most purposes (other than games and other things graphically intense), either of these virtualization softwares would be perfectly suited to running Windows full time.