Is hypervisor based virtualisation the correct way?

I thought a little bit about virtualisation this weekend after some interesting comments of a customer about his experiences with virtualisation. Are hypervisor based virtualisation mechanisms really the way to go? Think about the timing problems of VMware. The problems to virtualize dozens of timer ticks,eating away a good amount of the capacity of your system. Or the problems with I/O intensive tasks. You can throw more CPUs to the problem.But: I´m tempted to think, that solutions like branded zones are a more viable solution to virtualize for unix systems. You stay with a single kernel infrastructure mapped to different target operating systems by special mechanisms … like the branded zones, perhaps in conjunction with resource management. Looks more efficient to me than simulating the complete system.