If you do a lot of soldering I would think a hot air one would be the way to go. They are quite expensive though. We have three Edsyn 921 stations here and all work flawless other than we replace the tips about once a month or so. It seems the tips literally dissolve from the inside out. I had a tip a month ago that looked fine but was having a hell of a time soldering with. I had the temperature cranked up to 800ºF and it still wasn't working properly. After using my x-acto knife to clean some crud off that the sponge didn't I noticed that the tip actually fell right off leaving a nice hole. I don't think the problem is isolated to Cooper/Weller. I can remember having a tip for about 6 months before having to replace it.