This project does provide a very nice API and I think it can be very useful in some circumstances. However, I think client side storage is not as important as server storage. After all, a client can have many "client sides" and the appeal of storing stuff on the server is that all of them can be stateless and synchronized. I can see myself using this as a very nice cache mechanism for intermediate data, but the permanent storage would stay on the server.
<IMHO>SQL is not gross!</IMHO>