Well, there’s a big advantage in that they can produce genetically matched cells, and thus treatments that don’t require the patient to take anti-rejection drugs (which don’t always work) for the rest of their lives. THAT is what they’re so excited about, and with good reason.
According to a recent news article in the San Francisco Chronicle, Stanford University critics are now saying that the totipotent cells lines they're developing now (embryonic) " may not yield medical treatments for decades, if ever."
"These companies are essentially taking advantage of people's ignorance and fears to make a buck," said David Magnus, director of the Stanford Center for Biomedical Ethics---"
Meanwhile, according to the Sacramento Bee, the umbilical cord cells have a splendid therapeutic potential precisely because they don't involve so many genetic markers and thus are potentially useful even for non-related recipients. Supposedly you just have to have about 200 cell lines available to provide a workable match for anybody in the state of California.