I've been taking the time to actually set up the vFolders on my work and home evolution setups. When I first started using evolution I wasn't sure what the point of vFolders was considering you could already setup filters to shuffle stuff around into sub-folders. However now I've started using them in anger its a lot more obvious how powerful they can be.
The limitations of basic folder shuffling quickly shows up when you may want to read an email that can be in two categories, but cannot be in two real folders at the same time. For example I have a master vFolder which contains all work related email (i.e. to and from my work address). Under this I have various sub folders, one for team related stuff (via a distribution list), one for mail directly addressed to me, and a final one with all unread email. I also have one that catches all the admin messages.
I can read an email in multiple views however I can now just glance at the vFolder summary and see all my current unread messages are people's OoO messages and there is no waiting team mail. Its a lot easier than seeing I have 30 unread messages and having to plough through them to find out none of them are relevant right now.