All would make a good choice. For a commuter. The Karate Monkey will make the best off-roader if you want or need that capability. If you city commute or park inside an office the Ranger will be a little difficult to navigate. However if you have a long commute the Ranger with be much more comfortable.
For all of these bikes the most important point will be to have some good wheels built. If you buy machine built wheels retrue and tighten the spokes before riding and in either case have them retrued after a few hundred miles. That should ensure many reliable miles on the wheels. Running with a 30mm+ tire will also help.
Good luck and have fun
Craig
PS. I like the Ranger