Simply put: that's a risk you take for being an early adopter. Deal with it, there's a good chance it will happen with any/all early adoption startup products out there.
Version 1.0 came out in February of 2011. However, there were 7 Public Betas before that. The first one came out on October 4, 2010 [1]. By the time version 1.0 was released, Sparrow already had hundreds of thousands of users [2].
(Granted, October of 2010 still isn't ‘a few years’ a go.)