I don't have a lot of experience in robotics but have been subjected to some information recently. Panasonic Factory Automation is (I believe) the only company that supplies the robot and the welding power source together....other companies that use (for example: Fanuc and Lincoln/or Miller) seperate suppliers usually have problems when it comes to repair time.....Not to say that the equipment is not "good" but if there is a problem, the robot manufacturer will blame the power source manufacturer and vice/versa. with Panasonic, it is only one phone call.
just my 2 cents worth.....