I have a Euro Steam Revolution iron. The instructions say do not use distilled water. It says that if you have spitting, white deposits or brown stains coming out try using inexpensive bottled spring water. It explains that tap water with high levels of sodium can cause the white deposits. Iron, minerals and organic matter in tap water can cause discolorations on the fabric. The cleaning instructions advise using 1/2 vinegar and 1/2 water, pour into the tank, turn iron on, let it heat up. Then turn it off and cool for 10 minutes then shake vigorously. Let cool for another 10 minutes and then empty tank. Then rinse the tank with clear water until the vinegar smell dissipates. The instructions also say to empty the tank after each use. I've always left the water in the tank but after paying $300. for this iron I do as the instructions advise.

I now believe there is no iron that will remain drip-free after using it for a year or so. Every iron I have had, from cheap to an expensive "self-cleaning" iron, have become incontinent after 1-3 years of service. The last one I had, a Shark Pro, was spitting out rusty-colored water. Even after cleaning it out several times with vinegar, still spitting. Threw it in the trash.
I now use a dry iron and spray bottle. If I ever get another steam iron, I will get a fairly cheap one, as they all seem to be almost "disposable" and do not last for long.