LED, and virtually everything separately set up. That is I have all LED notifications off in the system settings and use BeBuzz for all of it. I don't use it for vibrate or sound, because BeBuzz goes through the media interface (and its volume setting) and I want sounds through the notification interface (and its sound), and in addition I can already customize that through system settings.
I only have a few contacts (a half-dozen) in BeBuzz but all of the main app categories are separately set for different LED colors and cadences, so I can at a glance know if I have a twitter, facebook, email (and from which account) or text, plus missed calls. I also have the app giving me a vibrate on call connect and disconnect, along with the no-service indicator flashing a distinct pattern as well.
I've had a couple of instances where it has silently stopped, but other than that it's been flawless.