To me, this shows why providing artificial deadlines is bad. They promised mid March for Alpha 3, and they released it mid March with some annoying known issues (as stated in the feature log) and what seems to be a fair amount of bugs.
So now the people who have been complaining about FD not committing to any hard date are happy, but the people who want a playable alpha are less than happy.
Personally, I would hope that this would serve as a lesson for the people complaining about delays. I'm a premium Beta backer and I can hardly wait until I can get my hands on the game, but I'd rather wait longer and play a beta that is mostly bug free and can be used as a way for FD to balance the game and polish the general experience.