Howard Dicus has a good video report at:
HD: ...They're trying to put butts in seats.
SU: But at the same time, are they making any money?
HD: No. No, they're probably all losing money on their interisland service right now...
HD: I think all of them, including Superferry, are struggling a bit. It depends a lot on how much worse the recession gets...
I'll just add that this fare war is much more expensive to HSF in losses per passenger than for any of the airlines. Mokulele, though, appears to have shallow pockets, and will likely go down first. But, Mokulele has the most comfortable looking seats to put your butt into and not get motion sick. It's a toss-up as to whether Go! can last longer than HSF. The only strong player in this is Hawaiian. If you got money to burn, I'd recommend Mokulele for as long as they are around.