It is unfortunate they've chosen opt-out. This is a tool for developers by developers. Are devs really cool with this, collecting information about them (even if it's anonymized) without their explicit consent?
Regardless of who will be the users, opt-in is the civilized and respectful way for this sort of thing.
I would think that devs would be the most okay with this concept, as they are the only ones that understand what data may or may not actually be transmitted, and the data collection goes towards helping people in the same seat (albeit different projects) as the maker of this product, developers.
Given that analytics really does let the authors fix problems and inefficiencies that users are having I would imagine people should "be cool" with it.
Regardless of who will be the users, opt-in is the civilized and respectful way for this sort of thing.