Pros : These molds, as all molds, are only as good as their primer and the primer that primer used. Getting the picture? YES, all molds should come with a twelfth generation photo copy of directions, because everyone is at sometime a novice mold user. HOWEVER, if one has a problem once, shouldn't one try to avoid whatever steps were taken the next time to promote a different outcome? These molds do work. And, yes, the resultant pieces do benefit from a brief fire polishing. (Perhaps fire polishing is another technique some mold users might wish to research prior to casting (haha) their mold to the trash.
I am certain the people who were disappointed in the outcome of the cabochon were disappointed also in the outcome of their efforts. Who wouldn't be? But, before scaring others off, why not provide a link to one of thousands of YouTube or Delphi or Warm Glass videos or other instructional medium? What a tremendous service to others seeking objectiveness in the product reviews.
Cons : Obviously, I'd like to see written directions and/or links to quality directions for using molds, fire polishing and related techniques.
Other Thoughts : See above and see you in the checkout line!