Re: Didn't take long
"Little comment has been made (so far) about the fact that this event showed up fairly soon after switching the device on."
This got mentioned in the press conference. They're pretty optimistic that the thing will pick things up quite regularly. It's a big universe with a lot of possible black hole binaries.
Speaking of which - this detection was also confirmation that such things actually exist (or "did" until these two merged) and that's another first. Up to now they've been purely theoretical.