This relates to why Kickstarter campaigns can be very lucrative to run - you raise funds without relinquishing any of your equity, which can later be sold for massive amounts of money (see: Oculus getting sold to Facebook)
They were clever and sold (reasonably functional) devkits, not final products for their kickstarter.
I won't regard them as fully successful until they release a final product that meets expectations (as in, facebook doesn't write them off as a loss)
Product wise, Pebble is the most successful so far, it was past the prototyping stage before for the first kickstarter (though adding extra features probably set them back) Right now they are up to major version 4 of their product. Long term, I don't think they will be more successful than Oculus.