My only real concern, whether it's warrented or not, is that with an alu frame and components, the flex will lead to metal fatigue and failure.
As for the ride, I don;t mind it so much. In some respects I wonder whether it even helps a little with taking out some of the road buzz.
Obvioulsy too much flex could give you a sense of unresponsiveness and poor handling. Again, whether that's the case or not, I don;t know.