As a general rule, it is a really bad idea, While it can work out, and I am certain people will chime in with how wonderful their experience has been, Microsoft has given the disclaimers and warnings for a reason. It is incomplete pre-beta software designed for testing. Even if your VM experience has been good, you never know when you may run into a hole or bug. Keep in mind as well that while the TP will be updated: 1) some of those updates can have unintended effects since everything is pre-release, and 2) if Microsoft follows previous practice both the eventual CP and release will require a new install instead of an upgrade.