I like Kadees and I like the 805s the best. they are not quite as prototypical, but I have lots of cars with them and they work well with each other. I have never had one break either. I found that trying to mix Atlas, Weaver, and Kadees did not work well for switching. They coupled OK most of the time, but uncoupling was nearly impossible. So I standardized on the Kadees for better operation.
Now in typical toy maker tradition, Atlas made the mounting holes on their bodies slight incompatible with Kadee in order to try to force you to use their product exclusively. I found that better than forcing, I put a #50 bit in a power drill motor and grind the rear hole in the kadee box into more of a slot toward the open end. Then the screws do not have to be forced. A 2x8mm screw is good for mounting Kadees to most Atlas cars.
the 700 series Kadees are very nice too and I think would be good if the whole fleet had them. since I have so many old Kadees, I don't want to change.
A local club tested all the various couplers available about 5 years ago and found the Kadees would handle about 5 times as much load as the other brands before breaking.
