While looking for something else I ran across this interesting post over at the Commute by Bike blog. It is an extensive report by Josef Janning on his use of a Quest velomobile to commute to work all year round, and includes a potted history of how he moved from commuting on a road bike, through several stages, till he reached his Quest. If it looks or sounds a little familiar this is the same Josef Janning who organised the Roll Over AMerica (ROAM) of last year.
He summarises his view nicely.
The velomobile exceeded these bikes and trikes in all dimensions. It allowed me to ride faster than on any of my other bikes, in more comfort, with better weather protection through all seasons, better luggage capacity, and on top of all this, with the most sensational feeling I have ever experienced on wheels.
The article is quite lengthy and informative and features a couple of excellent YouTube videos as well as several illustrative pictures. It is well worth a read.