Only negative thing I can say about it is size. Somehow I thought it is going to be bit bigger than what it is. But that is just me. If you see parts delivered with even high end soldering irons you do see that you are getting more then fair sized product.
It works good and it is necessary tool when soldering. Sponges thermally stress your iron tip and lower down the temperature very fast. This just cleans your tip. In some stages your tip can't be cleaned by the sponge anymore and this will clean it. For removing of the excess of the tin just lightly stab your soldering iron in it and for cleaning just strike the iron across the top and apply some pressure. Easy peasy.