Thus far, the pro-ESC arguments are all theoretical, not backed up by facts, whereas the ASC arguments are based on multiple real-world successes.
I won't dispute it. However, there are some very real theoretical advantages to ESCs over ASCs -- Kellmeyer's own article makes that point (if only to note that there are technical hurdles still to be overcome). Note also that the advantages of ASCs were also theoretical at one time -- so the fact that no ESC treatments currently exist, is not necessarily meaningful to the discussion.
Which is to say, it is not enough to hang our hats on "it doesn't work." Given time and money, it is very likely that some practical ESC-based treatments will be developed, just as has happened with Adult Stem Cells. It is also likely that the ESCs and ASCs would not be useful for the same things -- so we can't simply treat them as interchangeable approaches to the same set of problems.
We have to be honest, also, about the fact that one cannot help but be attracted to the medical possibilities, should ESC pan out. (That's the nature of temptation: it doesn't work if the potential results aren't attractive.) Once ESC does pan out -- as it probably will -- we will be hard-pressed to oppose it on anything other than moral grounds.
The utilitarian argument really does fail the first time a successful ESC treatment is found. That's why (just as with abortion) our only hope is to bolster the moral case against it.
But that IS the point. Those "theoretical advantages" have thus far turned out the be bullshit, despite the massive amounts of research already done in the area. The entire ESC position is based on hype and speculation---not real-world results. At some point, someone HAS to start pointing out that the emperor has no clothes on.