Just a little tip for anyone out there who has tried coping molding with a coping saw. I did this for the first time this past weekend and it was a lot of work to get the cut perfect with a coping saw and hand files. ( I am a little of perfectionist tho).
Anyways, I found that since I was using relatively small crown molding (was really bed molding), I was able to use my router and router table to make perfectly precise coping joints very easily. Just hold the wall side (ie the part of the molding that is flush against the wall, not the ceiling) of the molding flush with the router table, then mount a straight cutter bit in the router and simply move the molding into the cutter until you have removed the excess material from the profile. (This of course is simply short-stepping the coping saw step, you still need to make the miter cut to expose the profile). You do need to have steady hands and using a pencil to mark the profile does help.
Even though the bed molding was small, I did need to get a 1&1/4" depth straight cutter bit to go all the way through the molding. They had deeper ones, but I imagine on 3-4" crown, that this method would not be feasible. If you have done this with a longer bit on large molding, let me know how it worked out.