The ABB IRB 6400 is one of the most installed robots in the world the 6400R is the latest revison of this arm which have been used by most of the major automotive manufacturers for nearly 15 years. They have an excellent reputation for reliability and capability and as such are the industry standard. It is modular in construction and as standard the 6400 has 120kg capacity and 2.5m reach but there are several types available with capacities up to 200kg and reach up to 3.0m.
It should be noted that the arm is also very rugged and is less vulnerable to damage than many of its competitors. The robot is entirely powered by ac servo motors, the "rams" on the side of the arms are not hydraulic or pneumatic, they are simply enclosed mechanical springs. The springs and weight on the back of the robot make it very well balanced meaning the forces required to move the robot are remarkably small. Life expectancy or MTBF (mean time between failure) is largely dependant on service practises (once a year is normal) but we expect 6400's to last for at least 100,000 hours. Having said this we have seen very good examples with much more than this.