My iron at work was often on all day and also needed cleaning periodically when soldering to get shut of the black stuff or even to prevent it appearing.
I tried out one cheaper variable temperature iron off RS at work when my Weller went. It was fine but the tips didn't last very long at all. They don't sell these any more. I suspect that's one area Weller score on for some reason. The larger Weller tips also wet out well. Some of the cheaper stuff doesn't. I'd guess you would have noticed this if the Duratool one had a problem? A wet tip is handy at times.
No problems with CPC. I've bought several things off them over many years. Farnell too but I generally use RS.
I've been wondering about what to do with my Weller. It needs a new lead to the iron. I could make one up but as you mentioned they are getting expensive. Personally I would say 48w is about right providing there is some sort of temperature control – even higher wouldn't hurt. The power is there to maintain the temperature.
When I was a lad and had an Antex I didn't realise I also needed the sponge. I'd guess what happens is that the flux corrodes the coating so if it isn't cleaned off tips don't last and turn into a mess. I suspect the shape of Weller tips helps. Good heat transfer to the tip with little overheating further up it. They have a larger major diameter than any other I am aware of and just taper to the end.
John
–