I have a pair of Treks and a pair of Sprints. I've been wearing them a lot; around the house, running errands, a couple of times to the office, while working at home, and walking for at least 1hr/day.
Suffice to say that I wear traditional shoes rarely at best anymore, and that the VFFs seem to work as advertised. My toes are splaying, my soles are toughening (Sprints on gravel roads are a great foot massage and may have to do with the tougher soles), and my feet feel different, somehow; stronger. I've also noticed that walking in VFFs reduces pain from a herniated spinal disc.
In terms of odour management, I wash them. Also, a couple of weeks ago I borrowed some nylon sockettes from my wife, stuffed them full of aromatic cedar shavings from a local pet store, and whenever I remove my VFFs I stuff a shaving-filled sockette into each. It makes a big difference in terms of odour.
Further to this, I've read that sticking them in the freezer for 24 hours also works. I'm trying this tonight with my Sprints, which were due for a wash.