While the quality is lower, almost a throw away, the battery powered power roller is great. I have painted so much with these. I painted the front of my 4 story building with this power rollers. I painted my back fence.
The advantage is the battery powered unit holds 1/2 gallon of paint and then it slings on your shoulder. You manually control the paint flow by turning the pump on and off. No stooping to refill the roller.
http://www.amazon.co.uk/Wagner-Spraytech-Battery-Powered-Roller/dp/B0006JJSEY
