It will take more time to virtualize initially, but it will win you (big) time in the management part of Software. If you've a history on how many times you have to reinstall Office in the past (due to what ever reason, updates, end-user and what have you) or had to investigate issues in the package...
The reinstall of a physical Office installation can take some time. At least some visits to the coffee machine for the end-user. Using virtualization it can be done in 5 seconds... There basicly is no need anymore to investigate any problem with Office (unless all your users have the samen kind of issue off course), you do a reset of the Office layer and winthin 5 secs the Office installation is back to "out-off-the-box".
Also you can set a point in time to your organiszation the former version is not installed anymore. The only thing you need to do is "deactivate" which takes just a few seconds. Your end-users do not even notice the action it self. The do not have the application visible. When needed, you can activate it in those same number of seconds (CEO's secretary for example).
I know Office is hard to virtualize. If possible try to find a Supplier in your environment known to software virtualization. They should have a "out-of-the-box" Offiec layer for your that you can use and adjust. Ask your Symantec representative if you do not know any "scripting"-partner.
SVS is a great product. One of the best kept secrets with-in as outside Symantec!!!
Have great fun!