The old 6000/6100/6200 power supplies were a torroidal copper coil and basically bulletproof, they were AC output and the driver did the conversion to DC.
The new power supplies are off the shelf laptop/accessory switching power supplies. They don't last as long, they seem to average about 3-4 years. Life is affected by humidity and temperature, keeping them away from hot items and not stacking them as well as positioning them where humidity is below 70% greatly improves longevity.
We made this switch for several reasons, weight for shipping, universal voltage and only having to stock one model. Lower cost has kept the controllable pump pricing virtually flat since 2002 and the fact you can buy one anywhere in a pinch is a big advantage. While the torroids were nearly indestructible they were proprietary and unavailable in a pinch which was a disadvantage and they did periodically fail from water damage or overheating. The driver also was an issue as the rectifier was prone to overheating if the pump jammed and was at the practical limit for AC to DC conversion in wattage, this configuration used more power.
