I don't have a dog in this fight--I have as little to do with Microsoft
products as possible.

> I have also found our backups
> can run 10 mins slower with VSP on, compared to turning it off.

Your bpbkar log will show you how much of that is due to the initial
wait for n seconds of disk-quiet time.

> And to be honest, with or without VSP on, the files still get 
> backed up (excluding .pst and db related files or open processes).

Well, time-consistent backups of *open* files is rather the point, isn't
it?