One brand distiller will not significantly make purer water than another brand. Pyrex Glass is the cleanest material to heat water without adding contaminates back into the water. The problem with glass is that it's not durable and will crack if you drop it. We don't recommend using heat resistant plastic or aluminum. In this day and age, it's almost impossible to find water that hasn't been contaminated.
Rain falls through polluted air containing bacteria, smoke, and chemicals.
Our soil contains pesticides, herbicides, fertilizers, radioactive wastes and hundreds of other deadly chemicals which wash into our streams, rivers, lakes and wells. Our water supplies are filled with chlorine to kill bacteria and viruses. Chlorine and its by-products have been linked to cancer, heart attacks, diabetes, kidney stones and inflammation, gout and possibly even multiple sclerosis and muscular dystrophy. The water going into our house picks up lead from our lead pipes. Lead can cause severe neurological damage, particularly in children.