Best results I've had with hoses is when I have to replace a bent end with a plastic repair piece. The plastic repairs ends seem to seal better for me and seem to take abuse better than metal / brass. This is what I mean:
http://www.truevalue.com/product/Lawn-Garden/Hoses-Watering/Hose-Parts-Accessories/58-Inch-and-34-Inch-Female-Coupler/pc/10/c/146/sc/2395/13587.uts?refinementValueIds=6702As to the washers themselves... I find the basic yellow plastic washers seem to seal very well, but also have a tendency to fall out - but I use them mostly. The "natural rubber" washers never work for me, and I avoid them. So I don't have a great answer for a better washer!
