Excellent flowability, absorbs moisture well, melts and cures very quickly. You see, over the years I've used a large supply of silver-tin-lead-free resin core solder that I used to buy from Radio Shack and it's been really good too; then I ran out and bought some more silver tin cans from Bernzomatic a few months ago and it was just awful. Difficult to absorb, doesn't flow well, chars my soldering iron tip (I had to buy an ammonia block which I _never_ needed before), you get the point…