Pros : Being free of lead--a poison--is great; delivering terrible performance is not.
Cons : Very brief "waxy" state, i.e. extremely short time between liquefied and hardened. Dull finish.
Other Thoughts : Like many, I try to avoid any and all toxins in my environment whenever possible, and given the great reviews, I thought this product would serve me well. It didn't! It has an extremely high melting temperature, which is workable with good soldering skill, but it solidifies almost immediately after the iron is removed--this makes pulling a continuous bead along a seam extremely difficult, as any bumps in your glass that cause the iron to stop for the briefest of moments frequently means that the iron itself gets stuck as its trailing edge adheres to the already solidified solder behind it! I have tried different irons, and iron tips, maximizing temperatures, trying different fluxes with it, etc. The results have all been the same: terrible, and amateur looking solder lines!
I can't run away from this stuff fast enough!!!!