I'll believe it if and when they launch it.
That virtually uncaps scope creep, and because they've had a fairly open development process it's plain to see the time for not delivering a product past by a while ago.
The thing they can fail to do at this point is scale the player connections. If they manage to scale to thousands of players I'll be impressed.
As for Squadron 42, their track record is good in terms of sheer honesty (really not the same thing as as a prediction). A single player game being "feature complete" is pretty straight forward.
Edit: I have heard "we're almost done" before. So I'll believe it when it installs and runs.