Lots of great info in this thread!
My wife and I as well as several of our neighbors ride Dutch bikes for all of our commuting in Minnesota. We also have a collection of extras for friends to use when they're visiting us. My wife rides a Workcycles Gr8. I ride a Workcycles Opafiets most of the year but stick studs on an Omafiets for winter. We also have Gazelles, Batavus, Fietsbabrik and a couple of others. We have two bakfiets, one from Bakfiets.NL and one from Workcycles.
More on Dutch bikes:
City Bikes | LocalMile
IIRC the Workcycles Secret Service is Al?
Typically flats are easily repaired by pulling the tube out, patching, and sticking it back in so no need to remove the tyre or tube. The spreaders @
Stadjer mentioned work well when needed. Some Workcycles such as the Gr8 have a removable triangle on non-drive side that makes life a bit easier.
Flying Pigeon are amazingly poor quality. Once you find all of the parts not shipped with it and fiddle with adjusting things it's not awful but not nearly as smooth and easy riding as a Workcycles or Azor.
Generally a proper Dutch upright is more efficient than other bikes up to about 15-18 MPH. See link above for more.