When the 747-400 came out there were a lot of problems, many software related and there were frequent delays. When the 777 came out it was known as the cripple 7, my message light in the hotel was always flashing. Both aircraft became very reliable. I used to fly a lot on Tristars in the late 70s . They were frequently unreliable and that was years after they entered service. I'm sure once the A380 has had a chance to bed in and have the teething problems sorted out it will prove itself to be a very reliable aircraft.