My commute takes me from a suburban two lane road with a bike path, over surface streets in various states of disrepair, to downtown Los Angeles. To be fair, it is broken up by ride on the subway. I do feel somewhat "boxed in" when traveling through downtown, but I am able to use the far right bus lane, which is restricted to buses and right turning vehicles. I don't know if its luck or novelty or what, but I've had relatively few altercations with cars - most see you are on a bike and give a reasonable berth when passing. On the days when I ride all the way in, (about 24 miles door to door), my route runs the gamut of a four lane road with a bike path through Griffith Park, (one of the largest urban parks in the US), to a MUP along the Los Angeles River, ( a river in name only, but still relatively scenic), to a series of narrow winding two lane streets through Echo Park, Silverlake, and finally my destination at the University of Southern California.
Being in SoCal, we are blessed with 12 months of pretty good to outstanding weather, and have little to worry with river crossings, railroads and the like. The major complaint most riders have is with the condition of the roads, but with budget cutbacks in most urban areas, I'm sure its the same (or worse), in many other places.