r.e. MicroIslet
This is a very similar technology to PEG encapsulation, except that they are using an alginate. I don't personally have any insights as to which might prove the superior approach.
Fortunately, we have the (significant) advantage of being farther ahead in clinical trials...although, on the downside, their website seems to suggest an association with the Edmonton group, who have a very high profile when it comes to islet cell transplantation.